Add tree setup examples to the wiki

[tristan-f-r]

Currently, the only part of the docs that covers how to structure your tree is the videos and a single mention of them in the introduction. The docs, after "Actions and Conditions," as well as in "Buiding your Behavior Tree," should have example tree structures and their usages, possibly something even interactive (to see the individual scripts in nodes), if the current docs software allows that. This can also possibly prevent issues like #303.

I would be interested in working on this if it's approved.

[lostptr]

We do lack an updated video but with 3.0 coming and don't know if things are going to change yet again.