Migrate from TinyMCE-based editors to ProseMirror

[rsek]

ProseMirror seems to be The Future:tm: as far as FVTT is concerned. This isn't particularly urgent, since TinyMCE isn't deprecated yet. However, implementing it would get us some neat features like collaborative editing, which would be a great feature for a game that's often played co-op.

some candidates for implementation:

• https://tiptap.dev/ - renderless, extensible ProseMirror-based editor library, vue-compatible out of the box. collaboration requires subscription, unfortunately, but perhaps we could jerry-rig something from whatever foundry's doing under the hood
• https://github.com/rzuppur/RVPE - minimalist ProseMirror-based component
• use a wrapper component that just renders an HBS template. that's it. upside: the HBS template is already written by foundry :D

i think we have some unusual use cases, like putting oracle results in editors, that might benefit from additional helpers for custom extensions. in the mean time, the last option might be a good way to get us up and running.