Raw Image Bundle and meshless datasets integration

Added support of RawImage bundles into morphonet. Added also support of datasets containing only rawimages (still needs some work on the API side)

need to test loading datasts with and without rawbundles, on webGL and Standalones

also contains minor UI changes

at the moment (21/10/2022), almost all existing datasets have ra images as bundles, but no new are created (the converters are being fixed)