Switch to preinstalling Arduino IDE v2

This is a total rewrite of the app, using Electron. Version 1 of the
IDE, which we were previously preinstalling, is no longer supported.

Sadly, the rewrite is not published for arm64. But we have always
incorrectly omitted version 1 of the IDE from arm64 (see previous
commit) so no great loss.

https://phabricator.endlessm.com/T35401

config/arch/arm64.ini

@@ -16,6 +16,7 @@ apps_del =
 
 [flatpak-remote-flathub]
 apps_del =
+  cc.arduino.IDE2
   com.endlessnetwork.aqueducts
   com.endlessnetwork.blendertutorials
   com.endlessnetwork.dragonsapprentice

config/defaults.ini

@@ -478,7 +478,7 @@ apps_add_mandatory =
   org.gnome.TextEditor
   org.libreoffice.LibreOffice
 apps_add =
-  cc.arduino.arduinoide
+  cc.arduino.IDE2
   com.endlessm.photos
   com.endlessnetwork.aqueducts
   com.endlessnetwork.dragonsapprentice