fixes godotengine#82061
fixes godotengine#61556
Also, distinguish between main pack and DLC packs.
It's desirable to downloaded content to be as small as possible. This change avoids bloating non-main pack files with new versions of resources that are all read on startup and never used again. They have no effect if loaded after startup.
- project.godot/project.binary file
- extension_list.cfg
- app icon and boot_splash
- .ico and .icns files (these can still be opted in for DLC by listing them explicitly in the include filter)