photoproc: attempt create multithreading collect info about procs

[GermanAizek]

It may be useful especially when there are too many processes running in the background on enterprise servers.

[Atoptool]

I earlier experimented with multi-threading in atop myself and decided that I want to keep it out of the code. It makes the code more complex and error prone. Besides, when you use multi-threading in a few functions only it still might affect other (unforeseen) parts of the code.
In certain programs you can really benefit from multi-threading, but usually the entire code will be designed and written then keeping multi-threading in mind.