The logging conf files are baked into the docker image and provide only the minimal logging level. Generally this config can be updated by building a new docker image.

However, in some cases, it is helpful to be able to turn on/off debug logging to diagnose issues occurring only in particular clusters or environments. Sadly, there is no way to use env vars to configure that in StackStorm, so I need something more flexible to update logging conf files.

So, this expands the extra_volumes feature so that all of the python services can use it. Then, to update the logging conf file, just put the custom logging conf in a custom ConfigMap (managed outside of this chart), and then load it into the relevant deployments using extra_volumes values.

Resolves #269