[branding] Enable translations for the default show

- Just translate two simple strings, to avoid burdening translators,
 - Add Dutch translation already.

These translations are not yet processed by ci/txpull and push.

src/branding/default/lang/calamares-default_en.ts

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.1" language="en_US">
+<context>
+    <name>show</name>
+    <message>
+        <location filename="../show.qml" line="64"/>
+        <source>This is a second Slide element.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location filename="../show.qml" line="68"/>
+        <source>This is a third Slide element.</source>
+        <translation type="unfinished"></translation>
+    </message>
+</context>
+</TS>

src/branding/default/lang/calamares-default_nl.ts

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.1" language="nl">
+<context>
+    <name>show</name>
+    <message>
+        <location filename="../show.qml" line="64"/>
+        <source>This is a second Slide element.</source>
+        <translation>Dit is het tweede Dia element.</translation>
+    </message>
+    <message>
+        <location filename="../show.qml" line="68"/>
+        <source>This is a third Slide element.</source>
+	<translation>Dit is het derde Dia element.</translation>
+    </message>
+</context>
+</TS>

src/branding/default/show.qml

@@ -61,11 +61,11 @@ Presentation
     }
 
     Slide {
-        centeredText: "This is a second Slide element."
+        centeredText: qsTr("This is a second Slide element.")
     }
 
     Slide {
-        centeredText: "This is a third Slide element."
+        centeredText: qsTr("This is a third Slide element.")
     }
 
     Component.onCompleted: {