Allow duplicate categories wrt appconfigs

[jbazik]

Description

Allow blogs on the same site but attached to different apphooks to have duplicate categories.

In our case, we have two related blogs with different audiences ("blog" and "news"), and if we create a category (e.g. "awards") in one, we cannot create it in the other. Appconfigs enforce separation, so having "global" categories doesn't make sense.

Proposed solution

Add appconfig to the uniqueness constraint on BlogCategory.

Alternatives

It's possible to use one appconfig on multiple sites, and that's what we've done in the past. I'm trying to move away from a multi-site solution to something simpler.

Additional information

We're running django 4.2, djangocms 3.11 and djangocms-blog 2.0.7.