Load translations from mods

[achimmihca]

Actual behaviour

Currently, one can add custom profile images, themes, and code from mods.
However, there is no way to add or change translations.

Expected behaviour

Translations in a mod folder should overwrite and extend the translations that ship with the game.

Therefor, one could introduce a new mod subfolder Translations with the current properties files approach, e.g. the file messages_de.properties in this folder could overwrite the German translations.

Implementation

Currently, properties files are loaded from Resources folder in ResourcesFolderPropertiesFileProvider.cs
The logic could be extended to include properties files from mod folders.