Split Dashboard into Application and Dashboard modules
Split controllers into action and query controllers

- Action controllers always work with a command bus so an initializer
  provides it by default
Align controller inheritance to the new action/query concept
Set up ajax communication

- Ajax requests are based on jQuery.ajax but simplified with a custom
  plugin
- Notify.js and a second custom plugin help to communicate success or
  errors to the user
- Application makes use of zf-campus modules: ApiProblem and
  ContentNegotiation to unify handling of ajax requests in the backend
- Additionally a custom PSB invoke strategy ensures that one command
  handler can only handle one command