This adds the ability to configure hiding the logo on the deep linking page.
HIDE_DEEP_LINKING_LOGO defaults to false in the config.
The implementation also defaults to showing the logo if HIDE_DEEP_LINKING_LOGO
is missing from the config.

Up until now we relied on implicit loading of middlewares and reducers, through
having imports in each feature's index.js.

This leads to many complex import cycles which result in (sometimes) hard to fix
bugs in addition to (often) breaking mobile because a web-only feature gets
imported on mobile too, thanks to the implicit loading.

This PR changes that to make the process explicit. Both middlewares and reducers
are imported in a single place, the app entrypoint. They have been divided into
3 categories: any, web and native, which represent each of the platforms
  respectively.

Ideally no feature should have an index.js exporting actions, action types and
components, but that's a larger ordeal, so this is just the first step in
getting there. In order to both set example and avoid large cycles the app
feature has been refactored to not have an idex.js itself.

Currently Chromium based browsers and Firefox are supported on Android
Only Safari is supported on iOS

Set target='_top' inside anchor.

Courtesy of #6700
Follow-up to: #6784

This breaks the mobile deeplinking page
This reverts commit 532dadb245.

This update opens links in the full body of the window so deeplinks will work on iOS Safari when using the external API in an iFrame.

The ocnfig is not overridden early enough.

Fixes: https://github.com/jitsi/jitsi-meet/issues/6489

* Fix chrome extension banner

* Address reviews

Instead let the mobile OS take care of opening the URL
in the appropriate application. Without target _blank,
iOS 13.2.2 on Chrome will open about:blank and immediately
close the tab instead of opening the store.

There is no need to display the native app name as
raw html.

* 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.

🔥🔥🔥

Using anything non-serializable for action types is discouraged:
https://redux.js.org/faq/actions#actions

In fact, this is the Flow definition for dispatching actions:

declare export type DispatchAPI<A> = (action: A) => A;
declare export type Dispatch<A: { type: $Subtype<string> }> = DispatchAPI<A>;

Note how the `type` field is defined as a subtype of string, which Symbol isn’t.

This reverts commit 7c911eca96.

I'm dumb. We need global mode because otherwise lastIndex is not updated in the
regex object, which we rely upon, so this is intentional.

The URL cannot end in a /.

e729f0948c contained an off-by-one error:

URI_PROTOCOL_PATTERN includes the colon, so after applyting the regex we are
left with something like '//example.com/room' thus we only need to strip the
first 2 characters.

🤦

Looks like custom-scheme links no longer work in all browsers. They do on
Firefox, but the don't in Chrome and other default browsers.

So, switch to intent links on Android:
https://developer.chrome.com/multidevice/android/intents

Example:
```
<a href="intent://meet.jit.si/test123#Intent;scheme=org.jitsi.meet;package=org.jitsi.meet;end">Open Jitsi Meet</a>
```

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.

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

In order to be able to add analytics to the deep-linking pages the
lib-jitsi-meet initialization has been moved so it happens earlier.

The introduced `initPromise` will eventually disappear, once conference is
migrated into React and / or support for Temasys is dropped. At that stage, it
can be turned into a sync function which all platforms share.

* feat(Deeplinking): Implement for web.

* ref(unsupported_browser): Move the mobile version to deeplinking feature

* feat(deeplinking_mobile): Redesign.

* fix(deeplinking): Use interface.NATIVE_APP_NAME.

* feat(dial_in_summary): Add the PIN to the number link.

* fix(deep_linking): Handle use case when there isn't deep linking image.

* fix(deep_linking): css

* fix(deep_linking): deeplink -> "deep linking"

* fix(deeplinking_css): Remove position: fixed

* docs(deeplinking): Add comment for the openWebApp action.