feat: allow hiding enums

[janpio]

That enums are shown as blocks is nice - unless you have a lot of them and they are not that important to explicitly know about (again). I think it would be nice to have a global option per schema to show (default) or hide them.

Example:

This schema is more enums than models, and looks pretty complex here (and was a lot of work to move all the things around correctly), but really is pretty simple and straightforward with all the enums removed.