[macOS] Switch image generation to faster datastores (#1801)

* select datastore script

* add debug message

* add move-vm and helpers

* add error action

* formatting the script

* nits

* add missing quotes

* add synopsis

images.CI/macos/helpers.psm1

@@ -0,0 +1,26 @@
+<#
+.SYNOPSIS
+
+Helper functions to use in images.CI scripts
+#>
+
+Function Connect-VCServer
+{
+    try
+    {
+        # Preference
+        $global:ProgressPreference = 'SilentlyContinue'
+        $global:WarningPreference = 'SilentlyContinue'
+        # Ignore SSL
+        $null = Set-PowerCLIConfiguration -Scope Session -InvalidCertificateAction Ignore -ParticipateInCEIP $false -Confirm:$false -WebOperationTimeoutSeconds 600
+        $securePassword = ConvertTo-SecureString -String $VIPassword -AsPlainText -Force
+        $cred = New-Object System.Management.Automation.PSCredential($VIUserName, $securePassword)
+        $null = Connect-VIServer -Server $VIServer -Credential $cred -ErrorAction Stop
+        Write-Host "Connection to the vSphere server has been established"
+    }
+    catch
+    {
+        Write-Host "##vso[task.LogIssue type=error;]Failed to connect to the vSphere server"
+        exit 1
+    }
+}