Allow custom installation directory

[Latrolage]

Allow setting a custom installation directory. I tried to do something like that here: https://github.com/Latrolage/Photoshop-CC2021-Linux/blob/main/installer.sh feel free to just copy paste sections.

It saves the location of the prefix to $XDG_CONFIG_HOME/adobelinux/photoshoplocation and if $XDG_CONFIG_HOME doesn't exist it saves it to ~/.config/adobelinux/photoshoplocation I made the uninstaller script in the same repository read from those locations, but it may need more testing.

[MiMillieuh]

If you use the scripts in release or in the scripts folder, you can already use custom folder.