Push actions and action_results as assets to control CAS retention

Before raising this MR, consider whether the following are required, and complete if so:

• Unit tests
• Metrics
• Documentation update(s)

Description

For now, there isn't an explicit way to control the lifetime of blobs in CAS. This can lead to undesired situations where inputs are expired before they are fetched by workers if the job is queued for too long.

To control the lifetime of blobs, alternatively we can push related blobs as an asset into the remote-asset service with an explicit expired timestamp, to extend or shorten the retention of inputs/outputs.

Changes proposed in this merge request:

• Add AssetClient and its parser
• Update retention of Actions and ActionResults if related configs are set