Implement persistence layer
- mostly new implementation
- check the gtf test application first
(from redmine: issue id 286, created on 2018-01-22tgradl, closed on 2018-01-22)
- Relations:
- relates #285
- mostly new implementation
(from redmine: issue id 286, created on 2018-01-22tgradl, closed on 2018-01-22)