Detrusty

- Relax version requirement for python-dateutil
- Update dependencies
- Docker: update dependencies

- Push all operations to the source if there is only one sub-query
- Fix rare decomposition error
- Docker: update Python and dependencies

- Update dependencies
- Update documentation

- Add switch for exiting when checking endpoint accessibility

- Fix reading RDF-based configuration
- Update dependencies in Dockerfile

- Add feature for defining the source descriptions in RDF
- Create source descriptions in RDF
- Read source descriptions from RDF
- Deprecate JSON-based source descriptions
- Update documentation