restrict `oc oadp nonadmin` to non-admin tasks only.

[weshayutin]

Work with non-admin resources like backups, restores and backup storage locations

Usage:
  oc oadp nonadmin [command]

Aliases:
  nonadmin, na

Available Commands:
  backup      Work with non-admin backups
  bsl         Create and manage backup storage locations
  create      Create non-admin resources
  delete      Delete non-admin resources
  describe    Describe non-admin resources
  get         Get one or more non-admin resources
  logs        Get logs for non-admin resources
  restore     Work with non-admin restores

non-admin backup /restore
non-admin bsl creation / deletion ONLY..
describe and logs ONLY for nonadmin backups from the NABSL in the users current project.

That's it...
@stillalearner @mpryc @shubham-pampattiwar WDYT?

If there is only one nabsl in the project / namespace the oadp cli should AUTOMATICALLY use that one.
If there > 1 nabsl then prompt w/ --storage-location=

[shubham-pampattiwar]

Makes sense. The nonadmin command should only work with NABSL, not BSL - BSL management is an admin job.

For the auto-detection of single NABSL - good idea. Less flags to remember for the common case.