This new navbar component is used for every navbar in chat, full page or drawer, and any screen.
This commit also uses this opportunity to correctly decouple drawer-routes from full page routes. This will avoid having this kind of properties in components: `@includeHeader={{false}}`. The header is now defined in the parent template using a navbar. Each route has now its own template wrapped in a div of the name of the route, eg: `<div class="c-routes-threads">..</div>`.
The navbar API:
```gjs
<Navbar as |navbar|>
<navbar.BackButton />
<navbar.Title @title="Foo" />
<navbar.ChannelTitle @channel={{@channel}} />
<navbar.Actions as |action|>
<action.CloseThreadButton />
</navbar.Actions>
</navbar>
```
The full list of components is listed in `plugins/chat/assets/javascripts/discourse/components/navbar/index.gjs` and `plugins/chat/assets/javascripts/discourse/components/navbar/actions.gjs`.
Visually the header is not changing much, only in drawer mode the background has been removed.
This commit also introduces a `<List />` component to facilitate rendering lists in chat plugin.
We had safe-area-inset-bottom still set at a wrong place which was causing issues but was also useful to some cases. This commit removes it and ensures the affected cases are corrected.
Before this commit chat was applying a fixed height on everything under the `/chat` route. It's only really needed on the channel page with the composer at the bottom of the page.
This commits makes the following changes:
- moves height limitation from `#main-outlet-wrapper` to `.chat-channel`
- makes browse channel page and members list page full height and rely on main document scrollbar
- adds height computation for draft header and direct message creator block to ensure the height is correct when creating a draft channel
- makes chat index full height to rely on the browser scrollbar. As a result the <kbd> + </kbd> button used on mobile to create a direct message as been moved out of `<ChannelsList>` into the chat index template
- sidebar height was relying on chat setting a max height, as a result the height computation of sidebar has been changed to work correctly, especially with an opened keyboard on mobile or ipad
- Raises the scroll distance to 250px instead of 100px to show the arrow down button
- Always have a margin on drawer when showing channel list, removes this margin when the scrollbar is apparent
- Makes all scrollbar used in chat look the same through the chat-scrollbar mixin
- Ensures hover state is not persistent on channel row in mobile
- Makes the channel row full width on mobile
- Note this is also tweaking the UI a little bit as we are now using links/buttons in the header as needed
- It disables the find ideal channel in drawer mode, if loading `/chat` in drawer mode it will either reopen at the last position or just stay on index
