Add type comments to every methode

[IncredibleHannes]

In order to make document the code better, we need a documentation of every methods parameter and return type in the style of:

---@param hasTimetable function lineId -> boolean
-- returns [{vehicleID: lineID}]`

[Grisu118]

I like that, the annotation I added is from EmmyLua https://emmylua.github.io/annotations/class.html

I use VSCode with the following plugin https://marketplace.visualstudio.com/items?itemName=sumneko.lua which supports the annotations

[IncredibleHannes]

Thanks, I added it to my VSCode as well. This inspired me to set up luacheck as a linter, which will be integrated into the build process with #15