Add Mappers Toolset - Movement

[MartinMuzatko]

Implementing the following subfeature - Navigation

The full specification can be found in the feature docs on wiki:
https://github.com/inexor-game/code/wiki/Mappers-Toolset

[Fohlen]

@MartinMuzatko are you still interested in contributing a mapping UI? It's now getting into a stage where we will need the UI's to embedd them. Since you've clearly got some idea what should be in there, maybe you would like to help?

[MartinMuzatko]

@Fohlen I would really love to, but my time has been very limited in the past months :/
Thus, I can't participate in this anymore unfortunately. I hope I can help out another time though, when questions pop up.

Best,
Martin