rename file
changes, enhancements and refactoring

* move redis population into separate file dbrediscontroller
* add an environment variable ONLYWEB which will not start to analyse a DB
  and write to redis, instead re-use an existing redis dataset. It will also
  not listen to cahnges to datasets
* changes to /api/entities: always return number of datasets
* some refactoring: move code into files where it (better) belongs