Resolve file paths inside skins, soundsets and chart files with convertLR2Path

[staticssleever668]

Right now it's done for some but not all paths. This is needed on Linux as with #32 convertLR2Path() also resolves case-insensitive file paths.

An example of where this is an issue: https://manbow.nothing.sh/event/event.cgi?action=More_def&num=291&event=140.
The BMS files specify ad_hd.jpg, but the file in chart folder is named AD_hd.jpg.
2023-04-03 16:47:18.861 WARN [17227] [common_SDL2.cpp@150] [Image] Load image file error! Couldn't open /path/to/ABSOLUTE DARK/ad_hd.jpg