Feature: default timeout to commands

[fbarre96]

Sometimes, tools are very slow, locking a thread for other commands.
For example, an nmap scan on a very busy network, a nikto scan yieldings lots of false positive, a dirsearch looping...

For now, those "stuck" commands are detected manually in the scan tab where the start time is shown.
The pentester has to estimate if the delay is abnormal and manually double-click it and stop it.
If the tool has priority, it will be re-executed very soon...

Features implied:

• Add default timeout to commands objects
• add a tool status showing an timeout. Tools marked in this status would loose priority

[fbarre96]

Feature added in dev branch. can be unstable.
This issue will be closed after further testing.