Merge branch 'refactor' of https://github.com/polypheny/Polypheny-DB … #3616

Job	Run time
Integration Tests (Java 11) (mongodb)	9m 3s
Integration Tests (Java 11) (hsqldb)	14m 28s
Integration Tests (Java 11) (monetdb)	9m 27s
Integration Tests (Java 11) (postgresql)	14m 11s
Integration Tests (Java 11) (file)	1h 38m 16s
Integration Tests (Java 11) (cottontail)	14m 53s
Integration Tests (Java 11) (cassandra)	12m 45s
Integration Tests (Java 11) (neo4j)	13m 45s
	3h 6m 48s

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