Feat: Add configurable thread limit for parallel operations

Adds a "Threads" setting to the UI, allowing users to control the throttle limit for parallel tasks like driver and application processing.

This introduces a new textbox in the build options and updates the parallel processing function to use this configurable value instead of a hardcoded one.

Input validation is also added to ensure the threads value is a valid integer and is at least 1. The new setting is integrated into the configuration save/load functionality.

FFUDevelopment/BuildFFUVM_UI.ps1

@@ -9,7 +9,7 @@ if ($PSVersionTable.PSVersion.Major -lt 7) {
 }
 
 # Creating custom state object to hold UI state and data
-$FFUDevelopmentPath = 'C:\FFUDevelopment' # hard coded for testing
+$FFUDevelopmentPath = $PSScriptRoot
 
 $script:uiState = [PSCustomObject]@{
     FFUDevelopmentPath = $FFUDevelopmentPath;