Use event system to handle cascading deletes

See merge request !114

Child entities are now deleted by an event handler of their service
class.

RunAs is used to reduce permission lookups for internal method calls.

This upgrades Mockito to version 2.x.

Add caching for CRUD operations of DefaultEntityServiceImpl

See merge request !113

See #2.

Slighly refactored ControllerAdvices to include handling of Spring's
HTTP Exceptions. This fixes 500 status codes being sent instead of the
correct one.

Fixes GH-67.

Backport of d052fd73.

Slighly refactored ControllerAdvices to include handling of Spring's
HTTP Exceptions. This fixes 500 status codes being sent instead of the
correct one.

Fixes GH-67.

Upgraded to Spring Boot BOM version 2.1.

Migrate Pac4j to version 3.4

See merge request !111

Fix state updating of single Contents for /v2

See merge request !109

Daniel Gerhardt authored 6 years ago and Daniel Gerhardt committed 6 years ago

Use patch instead of full update.

Fix handling of content groups

See merge request !110

Partially reverts changes of 9d0255e7.
Added helper methods to Room which transform the ContentGroup collection
from Set to Map. Content IDs are now removed from groups when Contents
are deleted.

Refactor CRUD and legacy events

See merge request !108

Replaced the following events with StateChangeEvent:
* FeatureChangeEvent
* LockFeedbackEvent
* LockQuestionEvent
* LockVoteEvent
* LockVotesEvent
* PiRoundCancelEvent
* PiRoundDelayedStartEvent
* PiRoundEndEvent
* PiRoundResetEvent
* StatusRoomEvent
* UnlockQuestionEvent
* UnlockVoteEvent

Removed the following redundant events:
* DeleteAllLectureAnswersEvent
* DeleteAllPrepareationAnswersEvent
* DeleteAllQuestionsAnswersEvent
* DeleteAllQuestionsEvent
* LockQuestionsEvent
* UnlockQuestionsEvent
* UnlockVotesEvent

To trigger events, some code was migrated to use EntityServices instead
of directly accessing Repositories.

The hook methed was never called.

The event is now published for every single patched entity.

Add modifyRetrieved hook method for DefaultEntityServiceImpl

See merge request !107

`modifyRetrieved` can be overriden to modify Entities before they are
returned by CRUD methods.

Mock the correct method.

Include ContentGroups when retrieving Contents from service

Closes #30 and #29

See merge request !106

Implements #30.
Fixes #29.

Patching of child objects is now handled.