Refs #654 -- API: Writable event endpoints (#756)

* MKBDIGI-185: Added update/create to events

* MKBDIGI-185: Added validation for 'slug, 'live' on event endpoint

* MKBDIGI-185: Code formatting

* MKBDIGI-185: Added 'plugins' to 'event' endpoint

* MKBDIGI-185: Merge migrations

* MKBDIGI-185: Cleaned up static methods

* EBILL-5: Added delete endpoint for event

* EBILL-5: Merge migrations

* EBILL-5: Fixed imports

* EBILL-5: Changed plugins to only list plugins enabled for the event

* EBILL-5: Added clone event endpoint

* EBILL-5: Removed permissions check API test for events

* EBILL-5: Merged master, updated migrations

* EBILL-5: Updated api permissions check for CRUD on events

* EBILL-5: Removed 'unique_together' constraint on event model

* EBILL-5: Removed call to changed static methods in test

* EBILL-5: Changed Event 'has_paid_things'  to a property for consistency

* EBILL-5: Fixed created response code in documentation

* EBILL-6: Documentation fixes

* EBILL-6: Fixed typo

* EBILL-6: Fixed permissions

* EBILL-6: Added note on copying settings to documentation

* EBILL-6: Created model method for deleting sub objects on event before delete

* EBILL-6: Fixed typo

* EBILL-6: Re-added meta_data as read-only

* EBILL-6: Fixed permissions test

* EBILL-6: Added plugins issues check before live. Moved issues property from form to Event model.

* EBILL-6: Upped version number in documentation

* Add write support for MetaDataField

* EBILL-6: Expanded documentation for the clone endpoint, made behaviour of 'is_public' similar to 'plugins' for consistency

* EBILL-6: Re-added EventCRUDPermission

* EBILL-16: Updated documentation with permission model for the API

* EBILL-16: Added 'has_subevents' validation to ensure it cannot be changed once event is created.

* EBILL-16: Fixed event clone not differentiating between "not set" and "deliberately set to False"

* EBILL-16: Fixed event live validation

* EBILL-16: Added logging of live activated/deactivated

* EBILL-16: Fixed create event bug when no 'meta_data' supplied

* EBILL-16: Typo fixed

* EBILL-16: Added log display for "event created"

* EBILL-16: Enabling a plugin now calls 'installed' if applicable and log entries are added

* EBILL-16: Updated tests for events

* Do not allow enabling restricted plugins via the API

* Remove unused code

doc/api/fundamentals.rst

@@ -44,6 +44,25 @@ like the following:
           adding OAuth2 support in the future for user-level authentication. If you want
           to use session authentication, be sure to comply with Django's `CSRF policies`_.
 
+Permissions
+-----------
+
+The API follows pretix team based permissions model. Each organizer can have several teams
+each with it's own set of permissions. Each team can have any number of API keys attached.
+
+To access a given endpoint the team the API key belongs to needs to have the corresponding
+permission for the organizer/event being accessed.
+
+Possible permissions are:
+
+* Can create events
+* Can change event settings
+* Can change product settings
+* Can view orders
+* Can change orders
+* Can view vouchers
+* Can change vouchers
+
 Compatibility
 -------------