Tidying up Contributor Branches view in Share

[SystemFw]

Currently the project view shows all contributor branches, but this makes for a messy experience as a project maintainer, since I am forced to wade through all contributor branches ever created, unless the contributor happened to delete them themselves.
Fair enough that I'm not able to delete them since they belong to the contributor, but then maybe they should appear in a separate pane/list that I can hide.

[hojberg]

@SystemFw I'm assuming we're talking about this page here? https://share.unison-lang.org/@unison/base/branches

I think tabs and a search would do a lot.

[hojberg]

BTW, in the future, feel free to open tickets here: https://github.com/unisoncomputing/share-ui