- Update language choose dropdown to fit more languages

- add border-radius to filter list items
- use color as background of label for issue/pull view page

Both are possible on explore and admin panel

Collaborators have write access as default, and can be changed via repository
collaboration settings page to change between read, write and admin.

- Unified/Inline Diff-View Selectable

- User profile un/follow
- List user's followers/following

Most commit in Git are expected to follow standard of single header line,
followed by description paragraphs, separated by empty line from previous block.

Previously Gogs were treating everything as single header. Now we are trying to
render only first line as header, but following lines (description chunks) as a
verbatim.

With grey SHA1 labels, we should consider having also more subtle strips on
commits list. As current strips blend too much with grey SHA1 labels and top
bar, making hard to distinguish headers from content.

This removes remains from old design, that was not cleaned by previous #2068 PR.

Otherwise the fix will be overwritten by next _octicons.less update.

This is follow-up for 22b0dfbb35.