Nearest neighbor finder

Pull request #18: Postgres

Merge in EOSC-RS/nearest-neighbor-finder from postgres to master

* commit '01e71bcdbe267daa83073c6ded3acb9b1fb0e6b8':
  added search and training for users actions: ordered, viewed resources: 'datasets', 'publications', 'services', 'software', 'trainings', 'otherresearchproduct'
  fix logging levels
  added postgres training
  moved table config to tables_config.py in core
  Revert "moved table config to separate file in core"
  changed requirements.txt
  moved table config to separate file in core
  moved table config to separate file in core