Refresh: File Breadcrumbs

Created by: umpox

File Breadcrumbs

This PR:

• Styles revisions and repositories selectors as buttons
• Updates font size and spacing of file paths
• Update icon colors and spacing for all repository header icons
• Fixes color and outline of repository header icons
• Fixes outline issue on file path due to overflow clipping

Designs: https://www.figma.com/file/NIsN34NH7lPu04olBzddTw/Design-Refresh-Systemization-source-of-truth?node-id=3008%3A9805

Issue: https://github.com/sourcegraph/sourcegraph/issues/21051