This fixes get for multiple IDs and find.

This enables the manipulation of Contents before creation/update and
ContentGroups of Rooms after creation/update for API v3.

This enables the manipulation of Comments (creatorId) before creation
for API v3.

Closes !80.

These methods allow additonal application logic based on an created/
updated entity.

Tom Käsler authored 7 years ago and Daniel Gerhardt committed 6 years ago

See !77.

Spring Platform has been upgraded to the "Cairo" release.
This introduces new framework/library versions including:
* Spring Framework 5.0
* Spring Security 5.0
* Spring Integration 5.0
* Spring Data "Kay"
* Jackson 2.9

The following code changes were made as part of the migration:
* CouchDbCrudRepository uses new method names of CrudRepository.
  An extended version of CrudRepository is used to ease the migration
  process.
* AppConfig implements WebMvcConfigurer instead of extending
  WebMvcConfigurerAdapter.
* Servlet Filter and Maven exclusions for logging have been removed.

References:
https://spring.io/blog/2017/09/28/spring-framework-5-0-goes-ga
https://github.com/spring-projects/spring-framework/wiki/What%27s-New-in-Spring-Framework-5.x
https://github.com/spring-projects/spring-framework/wiki/Upgrading-to-Spring-Framework-5.x
https://docs.spring.io/spring-framework/docs/5.0.x/spring-framework-reference/
https://docs.spring.io/spring-security/site/docs/5.0.x/ref...

The Java default of handling .properties files as ISO 8859-1 encoded is
not contemporary anymore.

This is used by RoomController to allow requests to /room/~{shortId}.

This enables the manipulation of Rooms (shortId, ownerId) before
creation/updating for API v3.

EntityService can now retrieve the existing entity by itself before
updates.

These methods allow to perform actions based on the entity before the
CRUD operation is executed.

Additionally, added AnswerController for API v3.

Rooms are now updated when Content is created or deleted.

Update handling is NYI.

Tom Käsler authored 7 years ago and Daniel Gerhardt committed 6 years ago

See !75.

Renamed UserAuthentication to ClientAuthentication and moved it to v2.
API v3 uses its own model.

Finding by ownerId depends on a new database view and is NYI.

Default to 'vnd.de.thm.arsnova.v3+json' if no specific content type is
requested via Accept header or path version prefix.

Views are now checked for existence instead of creating them on every
startup.

Decide between 'vote', 'school' and 'abcd' target format based on count
of AnswerOptions.

When null was set as database key, the whole view would be requested
before this change.