feat: Further improved runtime of utilities (#618)

## Description

1. Improved runtime of Set-ModuleReadMe utility by building all test
files per modules using a thread each.
   
   Impact:
   
> Runtime of test runs ***before*** change on module 'Cognitive
Services'
   > 1. 20 s
   > 2. 17 s
   > 3. 18 s
   > 4. 17 s
   > 5. 17 s
   > </br>
   >
> Runtime of test runs ***after*** change on module 'Cognitive Services'
   > 1. 11 s
   > 2. 9 s
   > 3. 9 s
   > 4. 10 s
   > 5. 10 s


| Pipeline |
| - |
|
[![avm.res.key-vault.vault](https://github.com/AlexanderSehr/bicep-registry-modules/actions/workflows/avm.res.key-vault.vault.yml/badge.svg?branch=users%2Falsehr%2FreadMeSpeadup&event=workflow_dispatch)](https://github.com/AlexanderSehr/bicep-registry-modules/actions/workflows/avm.res.key-vault.vault.yml)
|

---------

Co-authored-by: Erika Gressi <[email protected]>

avm/utilities/pipelines/sharedScripts/Set-ModuleReadMe.ps1

@@ -1182,14 +1182,27 @@ function Set-UsageExamplesSection {
     ############################
     ##   Process test files   ##
     ############################
+
+    # Prepare data (using thread-safe multithreading) to consume later
+    $buildTestFileMap = [System.Collections.Concurrent.ConcurrentDictionary[string, object]]::new()
+    $testFilePaths | ForEach-Object -Parallel {
+        $folderName = Split-Path (Split-Path -Path $_) -Leaf
+        $buildTemplate = bicep build $_ --stdout | ConvertFrom-Json -AsHashtable
+
+        $dict = $using:buildTestFileMap
+        $null = $dict.TryAdd($folderName, $buildTemplate)
+    }
+
+    # Process data
     $pathIndex = 1
     $usageExampleSectionHeaders = @()
     $testFilesContent = @()
     foreach ($testFilePath in $testFilePaths) {
 
         # Read content
         $rawContentArray = Get-Content -Path $testFilePath
-        $compiledTestFileContent = bicep build $testFilePath --stdout | ConvertFrom-Json -AsHashtable
+        $folderName = Split-Path (Split-Path -Path $testFilePath) -Leaf
+        $compiledTestFileContent = $buildTestFileMap[$folderName]
         $rawContent = Get-Content -Path $testFilePath -Encoding 'utf8' | Out-String
 
         # Format example header