Add support for a Central Repository

[marckhouzam]

Describe the feature request

It is important for users to be able to find plugins easily.
Having a central repository for all plugins would allow this.

Describe alternative(s) you've considered

Having each plugin publisher have its own plugin discovery source. This would imply that when a user wants to install a plugin from a different publisher, the user would need to first add a new plugin source.

But even more importantly, there would be no way for users to find plugins of different publishers without somehow having learned about them somehow.

Additional context

More details to come.

[marckhouzam]

This was completed with the 1.0 release 🎉