correct behaviour of win_iis_webapplication when no applicationpool is specified (#61227)

* correct behaviour of win_iis_webapplication when no applicationpool is specified

* documentation for win_iis_webapplication apppool change

changelogs/fragments/61227-win_iis_webapplication-apppool-change.yml

@@ -0,0 +1,2 @@
+minor_changes:
+- win_iis_webapplication - now uses the current application pool of the website instead of the DefaultAppPool if none was specified.

lib/ansible/modules/windows/win_iis_webapplication.ps1

@@ -27,6 +27,12 @@ if ($null -eq (Get-Module "WebAdministration" -ErrorAction SilentlyContinue)) {
 
 # Application info
 $application = Get-WebApplication -Site $site -Name $name
+$website = Get-Website -Name $site
+
+# Set ApplicationPool to current if not specified
+if (!$application_pool) {
+  $application_pool = $website.applicationPool
+}
 
 try {
   # Add application

lib/ansible/modules/windows/win_iis_webapplication.py

@@ -40,6 +40,7 @@ options:
   application_pool:
     description:
     - The application pool in which the new site executes.
+    - If not specified, the application pool of the current website will be used.
     type: str
 seealso:
 - module: win_iis_virtualdirectory