Resolve mtype tool should be using embeddings

[jankrepl]

Right now it actually pings entitycore but that will be reimplemented via entitycore_mtype_getall tool.

So the idea is for it to do semantic search exactly like the resolve brain region does.

[jankrepl]

Note that after merging #330 you should also modify all of the tools that have the mtype_id query param and mention that one can use this resolve mtype tool to actually do English -> mtype ids. Same to what we do with brain regions.