Explore Adding oci Capabilities into tkn

This issue is meant to serve as a place to discuss possibilities for adding the features of oci into tkn. Closing this issue requires developing a plan (could include a demo too but not a requirement) that is discussed and approved in the tkn working group. It would also be helpful to gauge the thoughts of users of oci and Tekton bundles about their thoughts on the proposal.

With v0.18.0 of pipelines, Tekton bundles can be enabled via a feature flag. As part of supporting this feature, we should look into whether to add the oci cli into tkn.

Alternative solutions to adding oci could be to allow users to add oci as a plugin once #1178 is added. Additionally, we could look into supporting oci in a similar way to the hub cli (#1203).

What to consider as part of a proposal:

• UX - What would the proposed user experience look like when using oci features through tkn?
• Does oci's command structure align with tkn's structure (i.e. tkn <resource> <action> <args> <flags>)?
• Possible blockers for adding oci into tkn?
• High level overview of how oci would be added to tkn
• What alternative approaches could be used instead of what is proposed?

Start by reading the Tekton bundles section in pipelines.md and the experimental oci project. Compare oci's command structure with tkn's UX, review alternatives such as plugin support in #1178 and the hub approach in #1203, and gather user feedback. Done means a high-level proposal or demo has been discussed and approved by the tkn working group.