separate out completion ui from editing ui

[oxalorg]

Currently all user interface code is present in corgi-editor.el, but the problem is there are two (maybe more) types of user interface changing code.

One is all the editing related code, so things like Avy, Undo, Evil, etc.

Other is menu completion/interactive UI, like Ivy, Counsel etc.

I've separated out the completition ui into a separate package so it's optional and thus easier to replace (with vertico/consult etc)

• I've edited the Package-Requires by hand, is there a way to auto generate it?
• Maybe projectile should not be a part of completion ui, but it didn't feel right in editor either

[SignSpice]

Curious if there is something this is waiting for to be merged. Using this patch locally.