Improve Task Logging

[mfosterw]

Right now the same prefix is repeated many times for logging in the tasks.py file. Figure out a way to extract that prefix and place it after all the other prefixes automatically for all logging calls in the module. This is probably best done with a LoggerAdapter. You can see an example here.

[mfosterw]

This is now less relevant for the tasks module specifically but would be useful for the project as a whole. Along that note, the default format for log messages should be improved (i.e. I don't need process or thread numbers, at least in local)

[mfosterw]

I have taken a first tilt at this and failed to come up with a satisfying implementation. The issue is that, while it is probably possible to just prepend an extra string to the log message, in all the examples I saw it seems to be an unwritten rule to instead pass context arguments on to the formatter to insert them. However, I don't want to configure a format that depends on models specific to my app. I will probably fix it when I get rid of the django frontend, so I can switch the model __str__ methods to be short representations rather than display names (which now that I've written out sounds like something I might want to differentiate anyway). Once I can confidently call the object.__str__ in the log format, I can add a filter that depends on some general object being defined for the context, which feels much more sensible (e.g. it could be a request at the API level).