[WIP][FEATURE] field- and form-configuration to add a new location and attach it to the new event

todo: improve UI (modal?)
future todo: hide the fields, provide new Locations via Maps API in the suggest and fill the fields via JS with the data provided by the API
5 jobs for 24-integrate-events-with-frontend-editing in 1 minute and 42 seconds (queued for 3 seconds)