Allow priority setting, both from picker and parsed via !!!

[yunruse]

Added a 'priority' pill to the editor, making use of the dependency WrappingHStack to ensure that this doesn't squoosh up with the date and time pickers. A PriorityParser is added – rather similar to the other Parser objects – so "!!" can be used to impart a priority on the reminder, thereby fixing #195.

https://github.com/DamascenoRafael/reminders-menubar/assets/13365217/d90e4c02-a94f-4b41-820d-b81d6647285b

This was rather fun to work on 😅 I hope this barrage of pull requests isn't annoying!