* Add announce message length to UI and make a cvar for it
* Update comm console server-side trim to use the cvar
* Rely on the new OnTextChanged event
Because OnKeyBindUp only works for keys that have binds
* Add a similar indicator to nukies' war declaration UI
* Remove message length indicators for now cuz it requires the engine update
* Rename cvar slightly
* Refactor duplicated code to a helper method
* Remove message trimming from *Window class as it's better to live in the BoundUserInterface where the other message handling happens
* Rename to chat.max_announcement_length
(cherry picked from commit 8c5898b0065cd2cf196c0383bc99c57c0f11795b)
