Bam cache should remember loader used

[rdb]

Description

The bam cache should store the type of the loader used to load a particular model. When loading a model from the cache, it should check that the loader matches the loader it would have used to load the model if it had not been cached. If it does not match, it discards the cached version of the model.

Use Case

When changing the list of available loaders, such as when installing panda3d-gltf, a cached version of the model that was loaded by a different loader (eg. Assimp) may still be used by Panda. This creates user confusion.