- Remove network-activity "feature"
    - It wasn't in use
    - It relied on internal React Native components, bound to break anytime
- Show an infinite loading indicator
- Style it just like the LoadConfigOverlay
    - Since it kinda represents the opposite, an "unload" then SDK is done

Fixes: #312

It need not always exist, since it's created asynchronousluy on app
initiualization. Make sure we are ready for it.

I've seen backtraces because of this.

* fix(invite): decode the meeting name

* squash: try to make mobile join same encoded meeting name as web

* Decodes and generated texts for share and copy meeting info.

Decodes in all cases except when it contains a space, as it will generate wrong links when pasted/shared in external applications.

The only way to render the welcome page in reduced UI mode currently is to
hangup a call from the Android ongoing notification while in PiP mode.

In case wrong props are passed in, such as pointing to
an index that does not contain a value in the tabs
array.

This reverts commit 890151fa72.

By making the container 100% height and position relative, that
would cause it to overlap any static-positioned  elements below it.
The 100% makes it so that any watermarks intended for the bottom
of the page show up on the bottom of the page. However, it's not
needed because watermark stylings already try to position the
watermarks at the bottom.

🔥🔥🔥

This new version comes with an updated JSC runtime, so we no longer need to
depend on the updated version ourselves.

Remove caching of calculated styles, thereby removing
componentWillReceiveProps, by passing in base styles
and passed in styles when rendering.

To kill componentWillMount, call destroyLocalTrack after mount.
Navigation to the blank page was synthetically forced and no
UI issues were noticed, possibly because destroyLocalTrack may
already be async so destruction may already have been occurring
after mount.

For the most part the changes are taking the "static propTypes" declaration off
of components and declaring them as Flow types. Sometimes to support flow some
method signatures had to be added. There are some exceptions in which more had
to be done to tame the beast:
- AbstractVideoTrack: put in additional truthy checks for videoTrack.
- Video: add truthy checks for the _videoElement ref.
- shouldRenderVideoTrack function: Some component could pass null for the
  videoTrack argument and Flow wanted that called out explicitly.
- DisplayName: Add a truthy check for the input ref before acting on it.
- NumbersList: Move array checks inline for Flow to comprehend array methods
  could be called. Add type checks in the Object.entries loop as the value is
  assumed to be a mixed type by Flow.
- AbstractToolbarButton: add additional truthy check for passed in type.

* feat(welcome-page): Redesign.

* Style adjustments.

There are (at least) two changes that are breaking:
- defaultTab is gone
- The re-rendering logic looks to have been re-written so that
  passing in a new array of tabs causes a re-render, which can
  reset the currently selected tab.

The fixes involved removing defaultTab from each tab configuration,
as it is no longer respected anyway. Also, instead of letting Tabs
be uncontrolled and allowing it to set its own selected, which
would result in the first tab automatically being selected on
Tabs re-render, use Tabs a controlled prop to dicate which
tab is selected; this is accomplished by specifying a selected
prop.

It causes false positives when submitting the app to the Store. Use the new
permissions API in react-native-webrtc instead.

* Welcome page calendar ui improvements

* Addressing PR review comments.

Calendar integration ui

* feat(welcome-page): be able to open settings dialog

- Create a getter for getting a settings tab's props so the device
  selection tab can get updated available devices.
- Be able to call a function from a tab after it has mounted. This is
  used for device selection to essentially call enumerateDevices on
  the welcome page so the device selectors are populated.
- Remove event UIEvents.AUDIO_OUTPUT_DEVICE_CHANGED. Instead directly call
  setAudioOutputDeviceId where possible.
- Fix initialization of the audioOutputDeviceId in settings by defaulting
  the audio output device to the one set in settings.

* squash: updateAvailableDevices -> getAvailableDevices, add comment for propsUpdateFunction

* fix(welcome-page): css tweaks in prep for branded welcome page

- Watermarks should no longer depend on toolbar size. The left watermark made
  room for the toolbar when the toolbar was on the left side of the screen, but
  the toolbar has been moved to the bottom. The right watermark...well it'll
  clash with the vertical filmstrip but at least the margins will be consistent
  with the left watermark.
- Apply new font-family so fonts are more likely to be consistent across the
  app. Design likes SF UI and keeps requesting it so use it by default.
- Change sizings of welcome page header to be more responsive. This will help
  the header be scrollable when there is no additional content and the header
  overflows.
- Change colors of the welcome page header and remove background image that
  was in the header. Leave in the dom for the background image in case other
  deployments need to continue showing an image.
- Add a period to the title of the welcome page.
- Move watermarks dom location as it is not part of the header; it's part of the
  whole page.

* [squash] Size and font adjustments. Renaming.

It will only be requested if a user joins a meeting or flips the switch from
video to audio and back, but never as the first thing when the welcome page is
mounted.

Unfortunately, as the Jitsi Meet development evolved the routing mechanism
became more complex and thre logic ended up spread across multiple parts of the
codebase, which made it hard to follow and extend.

This change aims to fix that by rewriting the routing logic and centralizing it
in (pretty much) a single place, with no implicit inter-dependencies.

In order to arrive there, however, some extra changes were needed, which were
not caught early enough and are thus part of this change:

- JitsiMeetJS initialization is now synchronous: there is nothing async about
  it, and the only async requirement (Temasys support) was lifted. See [0].
- WebRTC support can be detected early: building on top of the above, WebRTC
  support can now be detected immediately, so take advantage of this to simplify
  how we handle unsupported browsers. See [0].

The new router takes decissions based on the Redux state at the time of
invocation. A route can be represented by either a component or a URl reference,
with the latter taking precedence. On mobile, obviously, there is no concept of
URL reference so routing is based solely on components.

[0]: https://github.com/jitsi/lib-jitsi-meet/pull/779