Introducing the Hostile Lockdown ability for AI Malfunction!

Grants a Malf AI a new ability - Hostile Lockdown, costing 20 CPU time.

- This ability activates all firelocks
- Closes all blast doors and shutters
- Closes and shock-bolts all airlocks that the AI can control, crushing anyone standing in a doorway when it happens.
- Sets the screen display to "Lockdown"

The lockdown can be reversed using the "Disable Lockdown" verb.
- Lifting the lockdown opens everything that was locked down by the AI. (Airlocks close again shortly after)
- Lifting the lockdown restores airlocks to a safe and functional setting.

Justification for this ability provided here: http://www.ss13.eu/tgdb/tg/latest_stats.html#mode_AI_malfunction

Discussion and poll relating to this update located here: 
http://tgstation13.org/phpBB/viewtopic.php?f=14&t=284

Please allow ample time for more opinions to flow in, and any revisions I need to make!
/tg/ PR version found here: https://github.com/tgstation/-tg-station/pull/3421