[TEP-0089] Enforce non-falsifiable provenance using SPIRE

[jagathprakash]

This is a tracking bug for the implementation of TEP-0089.

TEP-0089 is a proposal to enforce non-falsifiable provenance using SPIRE.

The PRs created to implement this issue are

• [X] PR-5039 [TEP-0089] - Spire Package
• [X] PR-5647 [TEP-0089] Apis to handle SPIRE signing and verification.
• [X] PR-5676 [TEP-0089] Modify entrypoint to sign the results.
• [X] PR-5902 [TEP-0089] Add a config map to support SPIRE initialization.
• [X] PR-6524 [TEP-0089] SPIRE for non-falsifiable provenance - IsSpireEnabled
• [X] PR-6527 TEP-0089: Refactor setting of "enforce-nonfalsifiability" feature flag
• [x] PR-6539 [TEP-0089] Add CSI volumes to the Pods which provide the SPIRE workload API
• [X] PR-6553 [TEP-0089] SPIRE for non-falsifiable provenance. Setup the test environment
• [x] PR-6627 [TEP-0089] Inject SpireControllerAPIClient into the Taskrun controller and reconciler.
• [ ] PR-6782 [TEP-0089] Enable the signing and verification of TR results and the TR status

[pritidesai]

Lets clear the milestone for now, we can bring it back if someone volunteers or we find someone to work on this. We do not have any owner at this time.