[API] Add group creation and registration functionality #1118

Job	Run time
Gradle Wrapper Validation	4s
API Docs Validation	10s
fbs-core.api / DB Migration Validation	2s
fbs-eat / Lint	45s
fbs-eat / Test	24s
fbs-sql-checker / Lint	33s
fbs-sql-checker / Test	24s
fbs-core.web / Test	2m 31s
fbs-core.web / Lint	1m 21s
fbs-runner.checker / Lint	39s
fbs-runner.checker / Test	1m 14s
Build Docker images	5m 40s
fbs-core.api / Test	2m 36s
fbs-core.api / Lint	51s
	17m 14s

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