With my previous changes Dolphin would fail to create the user directory if it didn't exist, and would dump all the configuration options in to the cwdir.
This was a bit more complicated to fix in a clean fashion, so I took to moving around code concerning user directories.
Instead of having GetUserPath serve a dual purpose of both getting and setting our user directories, break out to a new SetUserPath function.
GetUserPath will know only get the configured user path.
SetUserPath will set our user paths and setup the internal user path state.
This ending up being a lot cleaner overall, which is nice. Also less mind bending when attempting to read the code.
So now we won't dump all of our configuration in to the cwdir if ~/.dolphin-emu isn't found.
Fixes issue 8371.
The Load directory wasn't being properly reassigned when the user path changed, which causes a bunch of issues with things loading from the wrong
place when using the -U option in Dolphin.
The UI should decide on where it wants the user directory, not our core system.
This is in anticipation of some upcoming work on Android which will need proper user directory setting.
