Support entities instead of only nodes

I likely won't have time for this in the near future, but I think it might be valuable. If anyone would like to help contribute I'm happy to code review. Otherwise I'll take a look at it when I do have time. Thanks!

Contributing patch that allows getting paragraph usage across all the content entity types used.

The last patch is not working for a few people, contributing a new patch.

Handling empty content type ajax error.

There was an issue in #5, create this patch to handle ajax error.