proof courier: general cleanup and refactor, re-try after restart #1977

Job	Run time
Compilation check	27s
Docker build check	2m 43s
Format check	15s
cross compilation	8m 6s
run itests	8m 5s
run itests postgres	13m 9s
Lint check	2m 5s
go mod check	24s
RPC check	1m 1s
Sqlc check	18s
test vector check	58s
run unit tests (unit-race)	4m 46s
run unit tests (unit-cover)	2m 35s
run unit tests (unit dbbackend=postgres)	3m 39s
	48m 31s

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