Allow for special paths to be used for a profile's mod directory

[tomc128]

The Problem

At the moment, Ferium stores the profile mods directory as an absolute path (i.e. C:\Users...). Setting this value in the config.json file to include %appdata% rather than the absolute path fails, stating 'failed to create whole tree'. For me, I am sharing a ferium instance (including config file) on my network file server, so the inability to use a special path disallows the use of this shared executable if the absolute paths do not match.

Your Solution(s)

The ability for Ferium to parse special paths, namely %appdata% in the config file. This would allow the config file to be reused across multiple devices without the need to edit the path for each of them.