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

Story SW-300: fixing all the project path to execute the django application using the files in lib [to adhere to the LOFAR standards]