* ref(avatars): remove Avatar.js

- Rely on redux getting updated with new participant state
and any calls to getAvatarURL passing in the redux
participant state. This way the state within Avatar.js can
be removed.
- Clean up methods on UI.js. Because all state is in the
store, separate methods for updating the avatar aren't as
necessary. Instead centralize accessing of the avatar for
components outside of redux and centralize the call to
update avatars for non-react components.
- Controversial: cache a participant's avatarURL on the
participant state. Currently the participant's avatarURL
that is generated without jwt (which sets the avatarURL directly)
is not cached. Without cache, there can be many redundant
calls to APP.API.notifyAvatarChanged.

* Leverage middleware timing to diff avatars

One alternative implementation is to leverage middleware's
ability to intercept updates before and after redux has
upated and then compare avatarURLs.

* kill UI.getAvatarUrl

* profile button sets its own avatar url (solves update timing)

* remove calls to updating avatar outside of middleware

* update UI.js doc

* remove left over logic from initial implementation

* try to move local user fallback into selector func

* default to id 'local' in selector

The video will switch to the avatar and be tinted with gray. On the large view,
a text message indicating the user has connectivity issues will be shown.

It's designed to cover a container and give it a "tint" by using a color and
opacity.

When in wide aspect ratio,, show it with the local participant on top, and the
remote ones after, sorted by join order.

They will be stored in redux and the PageReloadOverlay will be displayed.

Note that this commit also introduces a subtle (and yet important!) change:
the location URL is now always set, regardless of the configuration loading or
not. This is needed in order for the retry logic to pick it up.

It's not supposed to go on top of everything, like an error would. It's tied to
a conference, so render it outside of the OverlayContainer.

On web Conference is pretty much all there is, but on mobile we have the welcome
page and the blank page. If we fail to load config.js, for example we will still
be in the welcome page *and* we want to show an error overlay.

* Removes unused config logic.

* Whitelists config options that can be overridden using the URL.

* Recorder login with credentials, not supported by externalconnect.

Jibri uses xmpp credentials to login, which is not supported by externalconnect, so we want to skip it till that is supported.

* Whitelist only config.js

* Extracts whitelisting in separate function.

* ref(analytics): centralize all event names

* squash: fix typo and alpha ordering

* squash: rename file to AnalyticsEvents to parallel lib-jitsi-meet

Rounded corners on the first and last buttons. Size of the hangup button
on hover.

The goal is to reduce usage on atlassian/aui. New components
have been created to display the settings panel. Language
selection will reach into i18n for state whereas moderator
options will keep state in redux.

Properly handle errors while connecting or joining a conference. Prior to this
patch, only errors on established conferences / connections were saved to the
redux store.

75bf7638b3 introduced this regression, state must
be assigned as an object, even though one would think it's automagically
initialized to an object. Oh well!

AtlasKit is not fully compatible with React 16. One problem
is PropTypes will not be defined on the React object. So,
add the prop-types shim to the popup bundle.

Adds more accessibility labels required for mobile automated testing.

These modification are not necessarily directly related to the
containing PR, I merely saw them while reviewing the containing PR.

Do the selection in mapStateToProps so the container itself doesn't need to
receive all the props that each overlay needs.

Each overlay is responsible for fetching their own props and for providing a
"needsDisplay" static method wich will be called with the full redux state and
should return true if the overlay needs displaying.

Also eliminate duplicated state keeping: the connection and conference error
states can be fetched from their respective base features.

* feat(notifications): prioritize based on type (appearance)

* squash: add return description to doc

Initializing UI features, like keyboard shortcuts, by chaining
onto APP.conference.init is not safe because init can fail,
skipping the initializing of UI features. This can happen when
the room is locked and then a failure event is dispatched into
middleware. I couldn't find a place to properly chain onto
in the APP.conference.init promise chain, primarily due
to the flow continued within middleware, so instead I
leveraged an existing listener for CONFERENCE_JOINED.

* Adds initial documentation for sipgw jibri.

Also explains enabling the people search service and the request/response that are made around sipgw jibri service.

* Fixes add people dialog to invite users and rooms.

No invitation is sent when there is nobody to invite.

* Reuse some recording strings, by using arguments.

* Make sure web also dispatches CONFERENCE_WILL_JOIN.

* Introduces new feature videosipgw.

* Fixes lint errors.

* Renames methods to use people, chatRooms and videoRooms.

* Updates to latest lib-jitsi-meet (dc3397b18b).

It was decided along with the mute participant dialog reactification
that these types of warning messages should not be toggleable--that
they should simply always display because there is no undo action.
As such, the component NotificationWithToggle is no longer needed.

* fix(notifications): throttle and batch join notifications

Instead of directly calling to show a join notification,
go through a specific method. This method will queue
names for display while a throttled function pulls
the names and shows a notification.

* squash: remove unused translation key

* squash: use default display name

* squash: move into participant actions

Refs: https://github.com/jitsi/lib-jitsi-meet/pull/648

It's possible for a track to be disposed but still on the redux store, before
the reducer removed it.