[BUG] apt: Repos keys must be readable by non-root user

[cpuguy83]

Expected Behavior

Specifying a repo key should not require explicitly setting permissions on the key file(s).

Actual Behavior

Keys must have the correct permissions already set (or defined in the source type).

Steps To Reproduce

extra_repos:
  - keys:
      msft.asc:
        http:
          url: https://packages.microsoft.com/keys/microsoft.asc

Building a spec with the above extra_repos on any apt-based distro will error with an unrelated error due to apt not being able to read the key.

Are you willing to submit PRs to contribute to this bug fix?

• Yes, I am willing to implement it.