* feat(base/modal): order props alphabetically

* feat(base/ui): added ripple color for tertiary button

* feat(prejoin): removed autoFocus from input and adjusted content

* feat(conference): adjusted RaisedHandCountLabel and added extra code spaces

* feat(prejoin): fixed content to fit tablets

* feat(conference): moved header button styles to navigation styles

* feat(mobile/navigation): updated header navigation button styles

* feat(prejoin): updated elements width, removed left inset

* feat(settings): fixed scroll, bottom insets and bounce

* feat(mobile/navigation): replaced native stack with stack navigator and other ui fixes

* feat(base/modal) added keyboard dismiss functionality

* feat(lobby) updated ui and start knocking if name is set

* feat(prejoin) updated ui and hide input if name is not required

* feat(prejoin) updated join button styles

* feat(prejoin) removed extra empty space

* feat(prejoin) updated disable join condition

* feat(base/modal) moved keaboard dismiss functionality

* feat(conference) updated auto knock condition

* feat(prejoin) updated button styles and disabling condition

* feat(lobby) updated styles

* feat(lobby/prejoin) updated styles for buttons and inputs

* feat(lobby/prejoin) updated contentContainer styles

* feat(lobby/prejoin) created shouldEnableAutoKnock helper

* feat(mobile/navigation) updated screens that have footer

* feat(chat/native) reverted style change

* feat(chat/native) reverted changes and added input vertical padding

* feat(base/modal) replaced headerHeight with top safe area inset

* feat(carmode/native) removed unused import and fixed linter

* feat(chat/polls/native) reverted style changes

* feat(base/modal) added isModalPresentation default prop

* feat(base/modal) made isModalPresentation optional

* feat(base/modal) headerHeight based on top notch devices

* feat(polls) updated styles

* feat(base/modal) updated comment

React Navigation v6.

Introduce navigation for all in-conference screens.

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.