This will allow to expose all those advanced features of the WM
operators to other parts of the code, like the python library context
manager, copy/paste code, etc.
This is expected to be a strictly no-behavioral-change commit.
Part of T91414: Unify link/append between WM operators and BPY context
manager API, and cleanup usages of BKE_library_make_local.
NOTE: This is strictly same code as what was before in WM area. Requesting review essentially to ensure that new names are OK for everyone.