Add a category for workflows

[j.jaffeux (Joffrey Jaffeux)]

I missed this bit, but it’s already the case, chat, assign, topic voting, ai,… are all plugins already using workflows plugin API.

@mcwumbly

What I mean by plugin API, is having the ability to add nodes with a plugin.. If you have suggestions for improving the workflows feature overall, that’s a good way to get them on the record, and let people discuss and vote on them.I think this would make a good topic in Contribute > Feature tagged workflows