Organizations: minor issues from initial pass at templates

[agjohnson]

Some additional notes, leftovers from #207, moved from #208 and pushed up to public beta timeframe:

• [x] Add a proper element for website link in organization header
• [x] Organization owners list avatars (and project maintainers list) likely looks weird with following text "... and X more". Probably replace the last avatar with a number label with the count? https://github.com/readthedocs/ext-theme/issues/137
• [x] Make sure organization delete modal works
• [x] #291
• [x] Make the custom SSO edit form work, it's not taking into consideration the initial form value currently
• [x] #290
• [x] Add right floating labels for organization on collapsed header
• [x] Add JS view for SSO edit page

[agjohnson]

Calling these all done for now, or at least addressable individually later.