Block Non-Enterprise Versions when Enterprise Version is Uploaded

[chrstinalin]

Relates to mozilla/addons#14849

Description

Blocks unlisted/listed versions 90 days after an enterprise version is uploaded.

Context

Enable the enterprise-channel waffle switch.

1. On a listed/unlisted extension, create a new version that uses the enterprise channel (i.e has browser_specific_settings: { gecko: { admin_install_only: true } } in its manifest).
2. New versions must also use the enterprise channel (i.e cannot be listed or unlisted). The user does not have the option to use listed or unlisted.
3. Existing listed & unlisted versions are automatically blocked after 90 days (Check BlocklistSubmission in admin).
4. If the user deletes all enterprise versions while enterprise blocks are pending (within the 90 days), the block will be deleted. If 90 days have passed, the block remains.
5. If no more enterprise versions exist, the user can continue to upload listed/unlisted versions.

Checklist

• Add #ISSUENUM at the top of your PR to an existing open issue in the mozilla/addons repository.
• Successfully verified the change locally.
• The change is covered by automated tests, or otherwise indicated why doing so is unnecessary/impossible.
• Add before and after screenshots (Only for changes that impact the UI).