Add Cosign Public Cert as Secret

Users deploying bigbang will need the cosign public key (generated by bigbang internally) stored in their cluster. The key will be referenced by all HelmReleases deploy by bigbang.

Determine:

• Workflow for publishing public key
• Process for adopting public key in bigbang deployments

Acceptance Criteria:

• Deploying BB with verifyOCI (or similar value) enabled, will include the public signing key needed to verify both BB Helm Charts and IB Images