This is a work in progress, but covers the coarse areas. This uses all-new classes to better describe what everything is, and to reduce the number of selectors we keep track of.
This is primarily layout for the list and not actually the final structure. For example, some buttons are missing and other areas are not styled correctly - the idea in this commit was to get things roughly in the right place and work on it.
Display an error on the splash screen with the spinner if the sync
request is not working, rather than just sitting there with a spinner
as if nothing is wrong.
Fixes https://github.com/vector-im/riot-web/issues/7148