Clicking a link of the sidebar will now open the drawer and load the correct channel.
This solution should correctly solve these cases:
closing drawer, clicking sidebar channel, should open the drawer on correct channel
visiting /chat then visiting / and clicking sidebar channel, should open full page chat on correct channel
This commits makes sure we correctly wait for the end of the transition to reopen the drawer on the correct channel/view. Also fixes a bug when previous URL was `/` and causing a double transition.
Also adds end to end system tests to ensure navigation scenarios are working correctly. This separation will make it easier to implement state in/out from chat.
Doing DOM operations in finally would cause them to happen even when the request was a failure. Consequence of these DOM operations would be new request, which would also end up in a 404, and so on.
This commit simply moves the DOM operations in the then block where it should be safe to make.
This is a followup of the previous refactor where we created two new
models to handle all the dedicated logic that was present in the
`ChatChannel` model.
For the sake of consistency, `DMChannel` has been renamed to
`DirectMessageChannel` and the previous `DirectMessageChannel` model is
now named `DirectMessage`. This should help reasoning about direct
messages.
