* Add initial primitives and tests for GPG related operations

* More tests and test documentation

* Move gpg primitives to own module

* Add initial primitives for running git verify-commit and tests

* Improve and better comment test

* Implement VerifyCommitSignature() primitive for metrics wrapper

* More commentary

* Make reposerver verify gpg signatures when generating manifests

* Make signature validation optional

* Forbid use of local manifests when signature verification is enabled

* Introduce new signatureKeys field in project CRD

* Initial support for only syncing against signed revisions

* Updates to GnuPG primitives and more test cases

* Move signature verification to correct place and add tests

* Add signature verification result to revision metadata and display it in UI

* Add more primitives and move out some stuff to common module

* Add more testdata

* Add key management primitives to Argo...