pfsd/intercom: Convert to use Protobuf

[VoyTechnology]

GoldenBadger Since you are the author or pfsd/intercom package its your call. Should we switch to Protobuf and gRPC? Since gRPC does not support using sockets, we might have to ask the normal pfsd for its status.

Not using sockets would also allow us to come a bit closer towards Windows version (given we solve other issues)

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Note: not tagging as this is an old project.