Add comprehensive test suite, fix minor issues, rename function and file names to match approved verbs (#708)

Scripts/FileIO/Get-ValidatedAppList.ps1

@@ -0,0 +1,24 @@
+# Returns a validated list of apps based on the provided appsList and the supported apps from Apps.json
+function Get-ValidatedAppList {
+    param (
+        $appsList
+    )
+
+    $supportedAppsList = @(Import-AppDetailsFromJson | ForEach-Object { @($_.AppId) }) | ForEach-Object { $_.Trim() } | Where-Object { $_.Length -gt 0 }
+    $validatedAppsList = @()
+
+    # Validate provided appsList against supportedAppsList
+    Foreach ($app in $appsList) {
+        $app = $app.Trim()
+        $appString = $app.Trim('*')
+
+        if ($supportedAppsList -notcontains $appString) {
+            Write-Host "Removal of app '$appString' is not supported and will be skipped" -ForegroundColor Yellow
+            continue
+        }
+
+        $validatedAppsList += $appString
+    }
+
+    return $validatedAppsList
+}