The tag options are not implemented out of concern for diff size.
This splits the context menu classes out to a new "iconized" style which is common across a number of context menus, including the UserMenu.
Some of the badge/sublist styles had to change to better accommodate the menu icon lining up.
This also contains the framework required for https://github.com/vector-im/riot-web/issues/13961
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.
