Set path for UUU patch script

[Mte90]

The wiki mentions to put the script file in the game folder https://github.com/sonic2kk/steamtinkerlaunch/wiki/UniversalUE4Unlocker

Can be handy a setting on stl to set the file or a folder inside stl settings where put those files with the steamid as name, as example.

[Mte90]

Also that doc page doesn't says what should be the file name for the script, reading the code seems that there is a file picker in the tool for that.

[Mte90]

So the UE4 script mentioned in the wiki is just a Bash script, also IGCSI it is not downloaded automatically so requires to download it manually.

[sonic2kk]

So this is just asking for a custom path for where to find the UUU script? Sounds reasonable! My time (and also motivation) have been low lately but anyone is welcome to contribute this. Sounds like it could just be a Yad file picker, the same as what we use for the likes of selecting the MangoHUD binary (:FL with Yad). There are quite a few examples in the codebase if anyone else wants to pick this up!

also IGCSI it is not downloaded automatically so requires to download it manually.

I recall an issue with IGCSI before not downloading, that was updated in d7701e4 to use dlCheck, but perhaps that is not used or not sufficient.

I'll need to investigate to know if this should be automatically downloaded, and if so, why it is failing to do so.