Made InputEvent as_text() return a readable and presentable string. Added to_string() overrides for each which returns a 'debug-friendly' version which is not as presentable but provides more information and in a more structured fashion. Use as_text() for UI display scenarions and to_string() for debug cases
- Moved Localization and InputMap editor code to separate files.
- Removed empty method _item_checked from project_settings_editor.
- Reordered some code for better readability.
