node package includes old modules

[somay]

dist/node/core/Identity.js, dist/node/core/Identity.js.map, and dist/types/core/Identity.d.ts in the master branch are no longer needed.
These modules are wrongly exported in my environment (node v15.11.0 on MacOS 11.3) and hiding the newer one: dist/node/core/Identity/index.js.