i18n: make the client translation ready

- add tx config file
- add source translation file
- changed some formatted string to be included in tr in case the
argument order need to be changed
- moved some ui text to code (e.g Credits)

Issue: #80359
Change-Id: I8ca846942a879f1e5753d042bb4cb44626c4c5ef
diff --git a/videooverlay.ui b/videooverlay.ui
index c06674c..8b244cb 100644
--- a/videooverlay.ui
+++ b/videooverlay.ui
@@ -20,7 +20,7 @@
    <bool>false</bool>
   </property>
   <property name="windowTitle">
-   <string>Form</string>
+   <string/>
   </property>
   <layout class="QGridLayout" name="gridLayout">
    <item row="1" column="1">