Fix member sidebar not showing on mobile.

Add Channel object.

i18n invites page.
Polish the bans page.

Fix: New members joining don't show.

Don't pass dispatcher in, just provide it globally.
Fix: Allow clicking through to profile from server sidebar.

- replaced many uses of `as any` with another more specific cast `as T`
- filled in missing typed for items that needed to be typed
  - new runtime code was added where necessary to satisfy the new types with comments
- added missing theme variable "sidebar-active" to the Theme variables
- forms using `react-hook-form` are now typechecked
- changed some instances of `target` into `currentTarget` while removing `as any` assertions

Add bars + header + sidebar to channels.