add option to deploy *.charm via url

What is the use case for having it stored in a git repository vs publishing it as the 'edge' version from Charmhub. Certainly that is the *reason* that we have edge releases (you can publish something that isn't the default that everyone else gets).

Is it because you want to try out someone's branch of a given charm? How does this work with things like resources and refresh and updates, etc.

It isn't hard to implement if we just treat it as 'just a blob to deploy' which we happen to get from a URL that isn't file://.

Yes, the original idea was testing branches, since automated publishing to charmhub is not supported yet (excluding echo $SECRET > .go_cookie). However, this use case is not relevant to me anymore.

Other potential use case:
A user may want to use github releases (or any other charmhub alternative) in parallel to charmhub. This may be relevant for proprietary charms?

Deploying *bundles* from url could be handy for example/test bundles created by community without trashing charmhub.

Deploying bundle *overlays* from url is even a stronger usecase: even when relying on charmhub for the main bundle, and convenience overlays still have to be stored elsewhere.