Hook up layer tree structure with frontend (#372)

* Hook up layer tree structure with frontend (decoding and Vue are WIP)

* Fix off by one error

* Avoid leaking memory

* Parse layer structure into list of layers

* Fix thumbnail updates

* Correctly popagate deletions

* Fix selection state in layer tree

* Respect expansion during root serialization

* Allow expanding of subfolders

* Fix arrow direction

Co-authored-by: Dennis Kobert <dennis@kobert.dev>

frontend/.eslintrc.js

@@ -62,6 +62,7 @@ module.exports = {
 		"no-console": process.env.NODE_ENV === "production" ? "warn" : "off",
 		"no-debugger": process.env.NODE_ENV === "production" ? "warn" : "off",
 		"no-param-reassign": ["error", { props: false }],
+		"no-bitwise": "off",
 
 		// TypeScript plugin config
 		"@typescript-eslint/camelcase": "off",