feat: Use Cirq's Gzip serialization

[drwillcharles]

We recently had some very large circuits that caused Superstaq server to run out of memory and crash. I think this change would help significantly to reduce the amount of data stored in the database.

Testing a very large circuit (with depth 36) this change reduces the amount of space used by a factor of 50.

We will also need to do some kind of integration test with the Superstaq server to ensure this doesn't break any tests.

[CLAassistant]

All committers have signed the CLA.

[drwillcharles]

Another possible solution instead of implementing cirq.to_json_gzip():

• Use gzip on the complete HTTP request bodies (Content-Encoding: gzip). This would require support from the server-side to unzip the payload but would make things simpler.
• On the server-side: change the circuit database fields to GZIP and migrate existing data.