Deprecate PSQ

[aarontp]

Two different compatibility issues:

PSQ / Datastore

PSQ is incompatible with datastore >2.0.0, and 2.0.1 was just released, and it's causing compatibility issues.
https://pypi.org/project/google-cloud-datastore/2.0.1/
GoogleCloudPlatform/psq#59

I created a PR to bump the version on PSQ since it's only a minor point release and compatibility should be OK:
GoogleCloudPlatform/psq#60

google-cloud-logging / python-error-reporting

Processing dependencies for turbinia==20190819
error: google-cloud-logging 2.0.0 is installed but google-cloud-logging<2.0dev,>=1.14.0 is required by {'google-cloud-error-reporting'}
The command '/bin/sh -c cd /tmp/ && python3 setup.py install' returned a non-zero code: 1

python-error reporting has a pinned version of google-cloud logging. They fixed it, but a release won't be out until after Thanksgiving.
googleapis/python-error-reporting#42

Workaround from that thread is to pin:google-cloud-logging==1.15.1

[aarontp]

Changing this to deprecate PSQ as it is deprecated and will go away in the new architecture in favor of celery and api/web servers.

[tomchop]

Bumping this, as it's creating dependency conflicts in dfTimewolf (log2timeline/dftimewolf#660). This will be fixed with the new Python API client, right?

[jleaniz]

We should be able to remove this dependency once we have a stable release that includes the API code and have migrated dftimewolf modules to use the new client. If you need to resolve the dependency conflict urgently then I'd suggest we explore some pinning magic as a temporary solution, since it may be another month or two until there's a Turbinia release without the PSQ dependency.