SPARQL conformance commands

[SIRDNARch]

Add SPARQL conformance commands:

1. setup, which prepares a QLever file and downloads the test suite files.
2. test, which runs the sparql conformance test suite and produces a JSON result file.
3. visualize, can be run in a folder containing JSON result files, will start a local server to look at results.
4. analyze, will index and start the server for a given test.

Currently only for the qlever engine using native or docker as a system.

Contains changes to the qlever commands like index, query and start.

Contains revised code from https://github.com/ad-freiburg/sparql-conformance to execute the test suite.