Add processes collector

[deadtrickster]

Based on process_info, aggregated by application.

application:get_application to get application of Pid (leader actually, but anyway).

TODO list of metrics

[deadtrickster]

It actually might be a good idea to separate data collection from rendering.
Properly structuring information about 200_000-300_000 processes takes 1-2 seconds on my VM, so it shouldn't be done synchronously when collecting all metrics.
A process with configurable interval writes to ETS.,,

OTOH processing 200_000 raises CPU usage to 20%(of one core) here. Which is a lot.