[UX] German keyboard layout qwertz (#6385)

Add support for German keyboard. It's mainly en_keyoard.lua with changed z/Z and y/Y.

frontend/ui/data/keyboardlayouts/de_keyboard.lua

@@ -0,0 +1,9 @@
+-- Start with the english keyboard layout (deep copy, to not alter it)
+local de_keyboard = require("util").tableDeepCopy(require("ui/data/keyboardlayouts/en_keyboard"))
+
+local keys = de_keyboard.keys
+
+keys[1][6][1], keys[3][2][1] = keys[3][2][1], keys[1][6][1] -- Z <-> Y
+keys[1][6][2], keys[3][2][2] = keys[3][2][2], keys[1][6][2] -- z <-> y
+
+return de_keyboard

frontend/ui/widget/virtualkeyboard.lua

@@ -660,6 +660,7 @@ local VirtualKeyboard = FocusManager:new{
 
     lang_to_keyboard_layout = {
         ar_AA = "ar_AA_keyboard",
+        de = "de_keyboard",
         el = "el_keyboard",
         en = "en_keyboard",
         es = "es_keyboard",