[REFACTOR][OBJECT] Consoldiate NodePtr/Ref/Hash/Equal to Object (#4603)

[REFACTOR][OBJECT] Consoldiate NodePtr/Ref/Hash/Equal  to Object (#4603)

* [REFACTOR][OBJECT] Consoldiate NodePtr/Ref/Hash/Equal and macros to Object.

Historically, we have classes like NodePtr/Ref/HashEqual.
After unified object protocol, these names are just alias of the object counterpart.
Moreover, there are helper macros defined over the places for defining these object.

This PR consoldiate the terminologies into the corresponding ones
in the Object system so we have a clean and consistent API moving forward.

* Update include/tvm/attrs.h

Co-Authored-By: Wei Chen <ipondering.weic@gmail.com>
* fix compilation

Co-authored-by: Wei Chen <ipondering.weic@gmail.com>