Java: generating nonfunctional compute client

[garrettjonesgoogle]

This isn't for review exactly, it's more to look at for amusement.

[bjwatson]

@garrettjonesgoogle How did you create this? Is everything in google-cloud-compute-v1/src/main/java/com/google/cloud/compute/spi/v1 hand-written using an existing GAPIC template, and then everything else generated with protoc from the proto2 files?

[garrettjonesgoogle]

@bjwatson I hand-converted the proto 2 file for InstancesService to proto 3 (and put that in compute_instances.proto), hand-converted the service yaml, used the gapic config generator to create the gapic yaml, then generated the client.

[bjwatson]

Ok, that makes sense.