fix(threads): fix proc mem info data race

[apragacz]

Description

This MR moves the mem / proc info retrieval into a separate struct with a RW mutex.
It also refactors several functions with more meaningful names.

Rationale

The current code tries to update the Options.Attributes in a background goroutine which is problematic, as it is concurrently being read. This can cause following error:

fatal error: concurrent map iteration and map write

which will cause the Go process to crash.
Updating the map separately with proper RW mutex in place seems to be the best solution to get around the problem.