Provide a general compatibility matrix for plugins

[lubosmj]

Some users are puzzled by plugins' compatibility versioning. It would be favourable to create a compatibility matrix to see which plugin versions support which pulpcore versions. Besides that, we may want to create a matrix for all supported features (e.g., which plugins support domains, which replicas, etc.).

Ref: pulp/pulp_container#1689 (comment)

[mdellweg]

Can this be automated?

[pedro-psb]

Getting the plugins compatibility with pulpcore can be fully automated, as that's predictably defined in requirements.

About the features, maybe some can be infered from the presence/absence of some files/snippets. Do you have ideas on that?
If that's hard to determine programatically, we could have this declared in a config file (possibly the plugin template one) and pulp-docs can use that to render the matrix.

This feature set is only about common features that pulpcore provides and plugins should have support for, right?
Do we have a definitive list of the features we want in that matrix?

[lubosmj]

The current list of domain-compatible plugins is wrong: https://pulpproject.org/pulpcore/docs/user/guides/create-domains/?h=domain#enabling-domains. pulp-file and pulp-certguard has been already merged into pulpcore.

[mdellweg]

And that is why the whole idea of a manual compatibility matrix is a bad idea.

The domain compatibility for a start is programmatically encoded. There is no excuse for this information to be outdated.