Merge #3891 Alternate mod dirs for validation and manual installs #1292

Job	Run time
build_NetCore (Debug_NetCore)	51s
build_NetCore (Release_NetCore)	1m 0s
build (6.8, Debug)	1m 47s
build (6.8, Release)	3m 9s
build (6.10, Debug)	1m 42s
build (6.10, Release)	1m 32s
build (6.12, Debug)	1m 29s
build (6.12, Release)	1m 49s
build (latest, Debug)	1m 37s
build (latest, Release)	2m 21s
	17m 17s

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