Add GPG check before commit message in repository table

[lafriks]

Just made this by accident while making #1678

Do not know performance implications for this so I did split these changes in other PR

Screenshot (combined with other PR):

[lunny]

I don't know why we need to put the lock there. Maybe put the commit build status is better?

[lafriks]

I don't know if status is that important in this view. GitHub does show GPG signature verification in repository file view but as I don't know what impact does it have on performance it's hard to tell if it's really that needed here also.

[lunny]

don't find github show GPG signature verification in repository file.

[lafriks]

You are right, github does not do that. I think this can be closed then

[sapk]

Signing the last commit can also be interpreted as signing/validating all the commit before since the hash of the last commit depend of previous commits (tree). So the only good information is that the last commit is signed. It would be impossible/hard to modify a old commit and still have newer singature valid.