feat: add scale bar layer

[josxha]

To do

• add scale bar as map layer
• fix left padding partly outside screen when padding 0
• fix top and left padding not the same
• lineWidth is now strokeWidth
• add lineHeight parameter
• default to black as color
• fix text rendererd partially outside of screen if the scalebar is very small
• scalebar alignment
• fix label overflow on right screen side
• fix alignment of scalebar if it is smaller than the text

Known problems

• When performing a fling animation against the top or bottom border, the scalebar increaes. I don't think that this is a bug of this pr, that's why it's not included here.

[JaffaKetchup]

LGTM I think. I also realised that this only supports one unit (metric), but maybe we can change this later.

[josxha]

I also realised that this only supports one unit (metric), but maybe we can change this later.

Yes, I experimented with an imperial scale a bit but it's a bit tricky since the calculations are metric and the the stop points of the scale bar need to be adjusted.

Are we ready to merge?

[JaffaKetchup]

Yeah I think ready to merge. Maybe something like Google Maps double unit scale bar would work well in future.

[josxha]

Maybe something like Google Maps double unit scale bar would work well in future.

Yep, would be a nice addition.