Optimize trigger when there are many processes

[giulianobelinassi]

Trigger is slow when patching 2000+ processes. Optimize it so it takes less time.

[giulianobelinassi]

Many improvements were added to trigger, such as:

• Reduce the number of ptraces.
• Avoid attaching/detaching a process every time we need to read its memory. Only attach once.
• Use process_vm_readv/writev instead of ptrace.
• Move process discovery into another thread.
• Avoid unecessary file reads and string comparisons on loops.