Introduce rest api

* Rest api is only reachable when authenticated.

* refs #16363
Add api for persons in application

* refs #16363
Add api for vacations for a given period

* refs #16363
Add api for sick notes for a given period

* refs #16363
Clean up of application configuration

* Remove xml service and controller definitions, use annotation based
  configuration instead for services and controllers.
Renaming of rest api parameters

* Rename 'start' to 'from' and 'end' to 'to' to have common terms.

* refs #16363