* feat(chat/polls/native): update ui

Remove tint for participant in large view
Change pinned indicator from border to icon
On stage view move screen sharing indicator from top to bottom
On stage view show pinned indicator instead of moderator indicator

* feat(lobby): lobby chat

lobby chat support
knocking participants list updates
knocking participants conditonal checks to show message button
handle lobby chat message events
lobby messages from or to moderators only

Co-authored-by: Fecri Kaan Ulubey <f.kaan93@gmail.com>

* squash: Drop typos.

Co-authored-by: Kusi Musah Hussein <kusimusah@gmail.com>
Co-authored-by: Fecri Kaan Ulubey <f.kaan93@gmail.com>
Co-authored-by: Дамян Минков <damencho@jitsi.org>

This event is the event host applications need to listen to for knowing when to
dispose the SDK from now on.

Since the introduction of breakout rooms it's possible that we navigate from one
meeting to another, so there will be several conference join / terminations.

In addition, local track destruction is now moved to SET_ROOM when there is no
room, aka, we are going back to the welcome page or to the black page.

It has been non-functional for a while.

Found via `codespell -q 3 -S ./lang`

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.

Also removed some no longer used styles.

🔥🔥🔥

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.

A reducer must always return a state or null to ignore it. When the color scheme
is undefined we should return the previous state.