Custom image from clipboard (#1157)

* Update how text renders in button and key

* Add a placeholder

* Add actual code and language entry

* Sort buttons

* Alter to keep original behaviour

* I HAVE OCD

* Add back legacy behaviour

parts/language/lang_en.lua

@@ -587,6 +587,7 @@ C. Gamepad
             bg_on="Normal BG",
             bg_off="No BG",
             bg_custom="Custom BG",
+            bg_custom_base64="Paste image as BG\n(PNG/JPG in Base64)",
             defaultBG="Default BG",
             resetDbg="Reset to default",
             lockBG="Lock BG",