Provide a mechanism for admins to manage the devfile registry

Problem

Currently there's no way for an admin to customize the available devfiles used as samples, or in the import from git (alizer) flow.

Goal

Admins should have an easy e2e experience which allows them to manage the devfile registries which are used on a cluster.

Why is it important?

Use cases:

1. <case>

Acceptance criteria:

1. <criteria>

Dependencies (External/Internal):

This issue is tracking the needed dependency: https://github.com/devfile/api/issues/499

Design Artifacts:

Exploration:

Note:

https://github.com/devfile/registry-operator/blob/main/README.md
https://github.com/devfile/registry-operator/blob/main/REGISTRIES_LISTS.md