i18n: update translations and provide powershell update script

- Update the tx source files.
- Provide a powershell update script as an alternative to our
  existing python script. The python script will need to be
  adapted for Qt 5.15.

Change-Id: Ibfefdca3657c4d893760ab62fb5c22386601c28b

update-translations.ps1

@@ -0,0 +1,14 @@
+[cmdletbinding()]
+param (
+    [string]$qtver
+);
+
+$clientDir = split-path -parent $MyInvocation.MyCommand.Definition
+$qtver = If ($qtver) { $qtver } Else { "5.15.0" }
+$qtMsvcDir = "msvc2019_64"
+$QtDir = "C:\Qt\$qtver\$qtMsvcDir"
+
+$tsFileNames = Get-ChildItem -Path "$clientDir\translations" -Recurse -Include *.ts
+$lupdate = "$QtDir\bin\lupdate.exe"
+
+Invoke-Expression("$lupdate $clientDir -ts $tsFileNames")