Fix user path sometimes failing on case-sensitive filesystems
Create the data directory if it doesn't exist
Apparently Qt does not do this automatically on Windows, so this fixes
another out of box bug on that platform.
This is a incremental release, meant for the eventual release
on the AUR.
However, it does include some important changes:
* Dalamud assets and runtime are now downloaded automatically
and also kept up to date for you.
* System libraries are now used for qt5-keychain and quazip if
found on your system.