Extension configuration

[RedMser]

• Allow customizing the detection, possibly using a UI
  • Per supported editor, include a list of rules which are checked for (window title, executable name, etc.)
  • But user can also edit these rules or add their own
• Possibly other things to configure, e.g.
  • Update timer frequency
  • Auto-close external editor when Godot is closed
• Remember if auto-docking is enabled or disabled, instead of forcing it on every time