add(scan): Start scanner gRPC server with `zebrad` #749

Job	Run time
Generate crates matrix	12s
Check crates matrix	2s
Build zebrad crate	29m 2s
Build zebra-utils crate	17m 33s
Build zebra-test crate	1m 33s
Build zebra-state crate	22m 3s
Build zebra-script crate	4m 57s
Build zebra-scan crate	20m 15s
Build zebra-rpc crate	22m 37s
Build zebra-node-services crate	3m 35s
Build zebra-network crate	7m 5s
Build zebra-grpc crate	2m 58s
Build zebra-consensus crate	17m 45s
Build zebra-chain crate	5m 16s
Build tower-fallback crate	59s
Build tower-batch-control crate	12m 48s
Open or update issues for building crates individually failures	0s
	2h 48m 40s

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