De-emphasize signed commits

[silverwind]

I think the current UI gives too much attention to signed commits. Big green box on commit page, green box on commit hashes. Signing is important but not so important that we have to plaster the UI with these colors. I think a simple "verified" icon should be enough when viewing the commit detail page, and no indicator at all on commit hashes.

[BlenderDefender]

For comparison: This is, how it looks like on GitHub:
Commit list:

Commit details:

[BlenderDefender]

Could look something like this:

[BlenderDefender]

Other layouts where this badge would appear:

[BlenderDefender]

Clicking the badge would trigger a modal: