* this is in preparation for future support in bevy & for more coherence & practicality
* overhauled metadata tooling
* overhauled most of the operators
* overhauled most of the UI
* all the basics & more work !
* unrelated: also started preping for auto_export operator removal
* removed a lot of obsolete code
* overhauled settings upsert
* added save & load of blenvy common settings
* removed most of the specific uis (mostly auto export)
* moved change detection logic out of auto export (wip)
* added helper to compare setting dicts
* cleaned up some incoherent naming
* stripped auto_export of a lot of its internals (wip)
* main settings ui overhaul: now components & auto export provide their own settings UI function