How to convert v3 Locus themes to new v4 format

[TrulloF]

@TrulloF
We published the python script that can help with the conversion theme from "Custom Locus V3" style to official Mapsforge V4
https://github.com/asamm/lomaps-mapsforge/tree/main/theme-v3-to-v4-converter
The conversion is not 1:1 but it can help to remove not supported attributes or convert DP units to "pixels" in V4

Needed to install some additional modules (e.g. lxml), but then conversion worked without a problem. There are several typos in the readme, but it wasn't to hard to figure them out  .