[feature] CSub GRPC features: reflection, healthcheck

[jeffmendoza]

For those running csub in production, it would be great to enable healthchecking: https://grpc.io/docs/guides/health-checking/

Also, the server is not supporting reflection, which makes using things like grpcurl require the proto files seperately.

Looks like just need some options here: https://github.com/guacsec/guac/blob/main/pkg/collectsub/server/server.go#L138-L146

Any concerns with enabling these?