Part 1 of https://github.com/vector-im/riot-web/issues/11262
This is all the visual changes - the actual wiring of the UI to the right places is for another PR (though this PR still works independently).
The help icon is known to be weird here - it's a bug in the svg we have. The tooltip also goes right instead of up because making the tooltip go up is not easy work for this PR - maybe a future one if we *really* want it to go up.
6b726a8e13