Prefer `TfHash` to `boost::hash`

[nvmkuruc]

Description of Issue

A large number of the non-python boost dependencies in the USD code base are dependencies on boost/functional/hash. pxr/base/tf has its own hashing mechanism that has already been successfully integrated across the USD code base. Switching to it reduces the number of dependencies on boost.

Steps to Reproduce

N/A

System Information (OS, Hardware)

N/A

Package Versions

N/A

Build Flags

N/A

[sunyab]

Filed as internal issue #USD-7883