Enhance app removal verification and error reporting (#735)

Scripts/CLI/Wait-ForKeyPress.ps1

@@ -1,4 +1,15 @@
+<#
+    .SYNOPSIS
+    Waits for user acknowledgement, then exits the script.
+
+    .PARAMETER ExitCode
+    Process exit code to return after acknowledgement. Defaults to 0.
+#>
 function Wait-ForKeyPress {
+    param(
+        [int]$ExitCode = 0
+    )
+
     # Suppress prompt if Silent parameter was passed
     if (-not $Silent) {
         Write-Output ""
@@ -7,5 +18,5 @@ function Wait-ForKeyPress {
     }
 
     Stop-Transcript
-    Exit
+    Exit $ExitCode
 }