Verify samples during CIs

Replaces Azure/azure-sdk-for-python#17999 for use in all language repos.

Author: heaths

eng/common/pipelines/templates/steps/verify-samples.yml

@@ -0,0 +1,19 @@
+parameters:
+  - name: ServiceDirectory
+    type: string
+    default: not-specified
+  - name: ScriptDirectory
+    type: string
+    default: eng/common/scripts
+  - name: Condition
+    type: boolean
+    default: succeeded()
+
+steps:
+  - pwsh: |
+      # If the last path segment is an absolute path it will be used entirely.
+      $root = [System.IO.Path]::Combine('$(Build.SourcesDireectory)', 'sdk', '${{ parameters.ServiceDirectory }}')
+      Get-ChildItem $root -Filter *.md -Recurse | ${{ parameters.ScriptDirectory }}\Test-SampleMetadata.ps1 -AllowParentProducts
+    displayName: Verify sample metadata
+    workingDirectory: $(Build.SourcesDirectory)
+    condition: ${{ parameters.Condition }}