eden should be able to use OCI registry credentials

[deitch]

Per this comment on an eve issue from @giggsoff, eden currently pulls any OCI images as an anonymous user. This appears to be true for both images run as part of eden start (e.g. redis) as well as those called from a test, e.g. this test.

eden should be able to:

• consume credentials for a registry from the default location, such that a prior docker login, whether as a developer or as a pipeline, will inherit those
• be able to override those (or provide when unavailable) via config file option or CLI flag or env var