Multiple fixes around commitments and group keys #1645

Job	Run time
Compilation check	44s
cross compilation	13m 48s
Docker build check	5m 38s
Format check	27s
run itests postgres	14m 24s
Lint check	3m 18s
go mod check	1m 22s
run itests	9m 28s
RPC check	2m 49s
Sqlc check	33s
test vector check	1m 29s
run unit tests (unit-race)	8m 12s
run unit tests (unit-cover)	4m 23s
run unit tests (unit dbbackend=postgres)	7m 17s
	1h 13m 52s

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