[xlcore] Add support for other xlcore native builds

[reiichi001]

XLCore now has a RPM spec, COPR repo, PPA, and Nix package, in addition to the AUR and MPR packages. These do not all install XIVLauncher into the same place.

The xlcore setup script will need to check where XIVLauncher.Common is (or use /usr/bin/xivlauncher, which most should be providing now).

Or alternatively, could the script be expected to bypass the check by providing a path to XIVLauncher.Core?

Here's a list of all the known install methods I'm aware of.

Arch - AUR
xivlauncher https://aur.archlinux.org/packages/xivlauncher
xivlauncher-git https://aur.archlinux.org/packages/xivlauncher-git

Debian/Ubuntu/Mint/Pop-OS/etc - PPA and MakeDeb/MPR
https://launchpad.net/~linneris/+archive/ubuntu/xivlauncher-core-stable
https://mpr.makedeb.org/packages/xivlauncher
https://mpr.makedeb.org/packages/xivlauncher-git

Fedora/SUSE - RPM distros
https://copr.fedorainfracloud.org/coprs/rankyn/xivlauncher/ sourced from https://github.com/rankynbass/XIVLauncher4rpm

NixOS
https://search.nixos.org/packages?show=xivlauncher&query=xivlauncher&channel=unstable