When the web client is completely ready, it triggers an event "web_client_ready" on the bus
Some Mail OWL components rely on that mechanism to be mounted
i.e. DialogManager and ChatWindowManager

When eveluating the action to display at startup, the webclient mechanism
implies that we push the location hash each time a relevant data is availaible
e.g. menu_id etc...

Now, before this commit, since the hashchange handler was bound before that evaluation
it was actually triggered each time the JQuery bbq pushed a url state (this is in the API)
doc: http://benalman.com/code/projects/jquery-bbq/docs/files/jquery-ba-bbq-js.html#jQuery.bbq.pushState

This undercutted the initial loading promise chain to finish and the event "web_client_ready" was never triggered
preventing everything that relied on it to be mounted

The DialogManager and ChatWindowManager were never available

After this commit, the webclient is artificially finalized, with the help of a new custom event
"webclient_finalize". So the event web_client_ready is trigger signalling to everyone it is in the dom

A lot of bug persist though, the start() of webClient sometimes returns a rejected promise

It is worth noting that the hashchange mechanism is largely outdated and will change
in a more reliable way in the near future with the conversion of the webClient to OWL
the drop of JQuery BBQ and the direct reliance on window.history.pushState
doc: https://developer.mozilla.org/en-US/docs/Web/API/History/pushState#:~:text=The%20state%20object%20is%20a,the%20history%20entry's%20state%20object.
and on the window's "popstate" event
doc: https://developer.mozilla.org/en-US/docs/Web/API/Window/popstate_event