Add duplicate column detection in EntityProvider #1990

Job	Run time
Build	2m 40s
Test with ECJ	1m 38s
Integration Test (h2)	2m 12s
Integration Test (mysql)	3m 10s
Integration Test (mysql8)	3m 16s
Integration Test (postgresql)	2m 37s
Integration Test (sqlite)	2m 2s
Integration Test (sqlserver)	3m 2s
Integration Test (oracle)	5m 48s
Publish	0s
	26m 25s

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