Story: As a quay user I want to be able to include cosign signatures part of repo-mirroring so that supply chain integrity remains intact when copying images from a remote registry into Quay.

Acceptance criteria: 

• during repository mirroring setup users can rely on Quay to include cosign signatures
• when active, repo mirroring will recognize cosign signatures that belong to tags captured via the repo mirroring filter and mirror those tags
• a visual toggle is present to enable / disable copying cosign signatures during mirroring
• by default the toggle is enabled