improve animal AI

[Palaxin]

​citing sanderd17:

What we mainly lack is some cleverness in the animal AI. About every animal would flee for an army of men, and never attack it. But many would attack a single person. The threshold is different for every animal species though, and some animals also prefer to attack in group. Some animals also chase (like lions), while others just want to get rid of you (like a rhino won't keep chasing you), or are too lazy to chase (a crocodile only attacks once). When that gets implemented, animals can be a bit more realistic, and be very annoying for scouting, but not interfere a lot when the game reaches the main combat phase. And making the first part of the game more interesting is still wanted I guess.

See also our discussion on ​IRC.

The existing code and the improvements should be shifted to a new component UnitAIAnimal.

[Palaxin]

this is very WIP, but I would like some feedback if I'm on the right track since this is my first major JS programming task

[Imarok]

Move tickets to Simulation as UI & Simulation got some sub components.

[Freagarach]

Refs. #1192, #1709, #1724, #3444, #3783.