Add provider command CRUD and manifest subcommands

These changes include:

- Merging initial work by bkearney@redhat.com
- Creating custom File validator to handle zip file encoding in
  import_manifest command
- Adding delete_manifest and referesh_manifest commands. The refresh
  command executes successfully, but the jobs worker doesn't
  successfully execute.  This seems unrelated, or least not caused by
  work done to implement the refresh_manifest command.
- Refactoring to inherit command actions and DRY up the code