Move XIVLauncher.Common.Unix to XIVLauncher.Core

[rankynbass]

What it says on the tin. This will allow updates to wine, dxvk, etc without needing to modify xivlauncher.common. This should hopefully allow for quicker updates to XL.Core.

XIVLauncher.Common.Unix can be deleted from the main project, or just left there. It depends on XIVLauncher.Common, and nothing but XIVLauncher.Core depends on it.

[rankynbass]

Quick way to check that the files moved are exactly the same:

cd /tmp
git clone https://github.com/rankynbass/XIVLauncher.Core.git --branch move-xl-common-unix
git clone git clone https://github.com/goatcorp/FFXIVQuickLauncher.git
diff -r ./FFXIVQuickLauncher/src/XIVLauncher.Common.Unix  ./XIVLauncher.Core/src/XIVLauncher.Common.Unix

Should print out something like this:

23c23
<       <ProjectReference Include="..\XIVLauncher.Common\XIVLauncher.Common.csproj" />
---
>       <ProjectReference Include="..\..\lib\FFXIVQuickLauncher\src\XIVLauncher.Common\XIVLauncher.Common.csproj" />