OSB-34: Setup of the preliminary implementation of the celery infrastructure, integration with the already existring django infrastructure and modification of the models to include and serve the RTSM plots

OSB-32: added additional filter field in the api requests to select the error types and url generation for the RTSM plots

OSB-29: Added appInitData reducer for async loading of app data like error types (removed from components/StationTestSummary.js)