Make the queue worker more aggressive with polling for new tasks when under load.

Also tune various defaults for the capture queue. Trying to get more throughput from workers by configuring better flags.
Catch SSL read errors and retry
Use expire_on_commit=False for SQLAlchemy sessions so we can read the attributes of a model instance after commit with no overhead
Adds caching for ApiKey models and access to builds to make requests from API workers faster.
Adds more logging messages around subprocess polling.

Trying to track down a bug where the process worker threads die and never recover.
Work around bug in subprocess module for reporting status of defunct processes.
Clearing up exception logging to help track down an issue
Improving worker logging messages
Writing more tests around the weird case of workers not finishing that I'm seeing in production.
Adding more debug detail to track down lost queue worker child tasks.
More clear logging message around outstanding tasks
Adds parent to work item for tracing in logs