Add RHEL `V6` container support [DI-375] #845

Job	Run time
Prepare environment	5s
jdks / get-supported-jdks	1s
Build with default JDK	3m 5s
Build with jdk-17	2m 54s
Build with jdk-21	2m 56s
Test pushing image (dry run) / prepare	2s
Test pushing image (dry run) / jdks / get-supported-jdks	1s
Test pushing image (dry run) / push (17, slim)	1m 23s
Test pushing image (dry run) / push (17)	2m 34s
Test pushing image (dry run) / push (21, slim)	1m 24s
Test pushing image (dry run) / push (21)	2m 31s
	16m 56s

Provide feedback