Queue based logging

[ky28059]

Implements generating a new logfile per run, and also fixes logging to the same file from multiple processes by using QueueHandler for all non-console logs in each process and running a separate logging process that writes the queued logs to file (and eventually to the DS websocket as well). The implementation is not as clean as before though, and it may be worth thinking about how all these different queues should be passed around.

[ky28059]

I think having CameraSources construct the pipelines is definitely cleaner currently, it just might get a bit tricky when streaming requires a different port per pipeline per camera source.

[e3l]

hm yes, that is a very good point. Perhaps our options are

1. to keep the old scheme and have each source to pass all the queues when calling process, or
2. in each camera source's pipelines arg, pass either a Pipeline class (as it is rn) or a (Pipeline class, port#) tuple

[e3l]

Alternatively, maybe a central streaming coordinator class can have a register function which handles the port assignment, and we pass an instance to every source, to be passed to every pipeline?