[pip] Move protobuf pin from query to gear

[daniel-goldstein]

protobuf was pinned not because it is a direct dependency of hail but because the version of google-cloud-profiler that we use is incompatible with greater versions of protobuf despite not putting an upper bound on its pin. However, the current solution of pinning it in hailtop/requirements.txt and python/requirements.txt is problematic in three ways:

1. Users of the hail pip package cannot use a newer version of protobuf if they want to
2. The protobuf version is only a problem for google-cloud-profiler, which we only use in the batch/ci/auth services, not the hail package
3. protobuf no longer a transitive dependency of anything in hailtop/hail, so why include it (and why include it twice?)

This is all fixable by moving the protobuf pin "up" to gear/requirements.txt, where we also install google-cloud-profiler. Whether or not we should be upgrading google-cloud-profiler to remove the protobuf pin is a valid but unfortunately thornier issue since google-cloud-profiler statically linking libc breaks libsass. This allows us to punt on that upgrade while freeing users of the protobuf restriction.