add function to download and install vsix

images/win/scripts/ImageHelpers/InstallHelpers.ps1

@@ -161,6 +161,74 @@ Hashtable for service arguments
     }
 }
 
+function Install-VsixExtension
+{
+    Param
+    (
+        [String]$Url,
+        [String]$Name
+    )
+
+    $FilePath = "${env:Temp}\$Name"
+    $ReleaseInPath = 'Enterprise'
+    $exitCode = -1
+    $retries = 20
+
+    while($true)
+    {
+        try
+        {
+            Write-Host "Downloading $Name..."
+            (New-Object System.Net.WebClient).DownloadFile($Url, $FilePath)
+            break
+        }
+        catch
+        {
+            Write-Host "There is an error during $Name downloading"
+            $_
+            if ($retries -gt 0)
+            {
+                $retries--
+                Write-Host "Waiting 30 seconds before retrying. Retries left: $retries"
+                Start-Sleep -Seconds 30
+            }
+            else {
+                Write-Host "File can't be downloaded"
+                $_
+                exit 1
+            }
+        }
+    }
+
+    $ArgumentList = ('/quiet', $FilePath)
+
+    Write-Host "Starting Install $Name..."
+    try
+    {
+        $process = Start-Process -FilePath "C:\Program Files (x86)\Microsoft Visual Studio\2019\$ReleaseInPath\Common7\IDE\VSIXInstaller.exe" -ArgumentList $ArgumentList -Wait -PassThru
+    }
+    catch
+    {
+        Write-Host "There is an error during $Name installation"
+        $_
+        exit 1
+    }
+
+    $exitCode = $process.ExitCode
+
+    if ($exitCode -eq 0 -or $exitCode -eq 1001) # 1001 means the extension is already installed
+    {
+        Write-Host "$Name installed successfully"
+    }
+    else
+    {
+        Write-Host "Unsuccessful exit code returned by the installation process: $exitCode."
+        exit 1
+    }
+
+    #Cleanup installation files
+    Remove-Item -Force -Confirm:$false $FilePath
+}
 function Get-VS19ExtensionVersion
 {
     param (