Provide a way for users to see a list of available MV3 extensions

[anewuser]

I believe the only current way to find out if an extension uses Manifest V2 or V3 is to inspect its manifest.json file.

Adding an MV3 filter will make it easier for users to find extensions that allow them to control host permissions. It will also encourage more developers to migrate their extensions to MV3 sooner.

┆Issue is synchronized with this Jira Task

[KevinMind]

Old Jira Ticket: https://mozilla-hub.atlassian.net/browse/ADDFRNT-217