Allow developers to verify there jar file with a sign key

[TheMeinerLP]

Is your feature request related to a problem?

Not direct related to a problem its just a nice to have feature.

Describe the solution you'd like.

1. Have on the profile a option to add gpg keys of a use/organization.
2. Sign jar files over the hangar publish plugin
3. Get a badge/status on the plugin to see the developer use gpg key to sign there plugin
4. A rest api endpoint for other developers to get the key to test the plugin for a source of truth.

Describe alternatives you've considered.

Don't implemented or just the option to add and get the key from the rest api and ui.

Other

Mockup was i made with simple html editing

I added also a small verified icon on the end of the plugin name.
Also a example of orga ui


Here a example for the whole plugin list