[Feature] Refactor details screen - merge view and edit

[patrickunterwegs]

TODO:

• Alarms
• Attachments
• Attendees
• Categories
• Collections
• Comments
• Contact
• Dates
• Location
• Parents
• Recur
• Resources
• Status, Classification, Priority
• Subnotes
• Subtasks
• Summary
• Description
• Url
• Always update only field that was changed (never the whole iCalObject)
• Refactor date fields in single elements (also movable)
• Check location and geofencing
• Restrict editing for pro on Google Play