Consider moving `Base37.kt` and `Cp1252Charset.kt` to their own module

[Jire]

Since the implementation doesn't have dependencies, some projects may want to include it but without including the whole module's dependencies.

These could be part of one module perhaps called util, which is where all misc utility code that do not have dependencies may go. They are quite useful implementations on their own for even non-RSPS projects.

[Z-Kris]

I'll refactor them and a few other things into their own modules in the future, even if it means having a single class in one module. This'll likely be done after the big rewrite in the previous issue.