This commit moves mainly two functions from `ui.js` to `message_live_update`,
`update_message_in_all_views` and `update_starred_view`. This is done in favor of
eliminating `ui.js` and also these functions are more closely related to
`message_live_update` module than to `ui` module.
We also move `show_message_failed` and `show_failed_message_success` to `echo.js`
for cleaner seperation of responsibilities.
This lets us simplify the long-ish ‘../../static/js’ paths, and will
remove the need for the ‘zrequire’ wrapper.
Signed-off-by: Anders Kaseorg <anders@zulip.com>