Add Support for querying Third party storage backends

[khrm]

Feature request

Results should support querying logs from third-party backends like Loki, Splunk, and Google Cloud Logging,
Result RBAC can solve some of the issues faced when viewing logs for different users. Results also provide a standardise way for clients to view the pipelinerun logs.

Use case

1. Trying to view forwarded logs.

[khrm]

/assign @khrm

[khrm]

This will be resolved by #782

[khrm]

/close