refactor: migrate Boost.Python syntax to nanobind

[SYMSCAE]

This PR is the initial port that migrates the original Boost.Python bindings to nanobind as mentioned in diffpy/pyobjcryst#88, noticed future improvements will be mentioned in TODOs but will be addressed in future PRs.

[SYMSCAE]

@sbillinge Please see if this is what we want.

[stevenhua0320]

@SYMSCAE This PR is still failing. I suspect it is because we haven't updated the dependencies for this package (libdiffpy and pyobjcryst). So, in order to make it build properly, we might need to update its dependency so that we could test whether it would work. @sbillinge We might also open migration branch on libdiffpy and pyobjcryst so that @SYMSCAE and @joeseaer would work on that.

[sbillinge]

@SYMSCAE This PR is still failing. I suspect it is because we haven't updated the dependencies for this package (libdiffpy and pyobjcryst). So, in order to make it build properly, we might need to update its dependency so that we could test whether it would work. @sbillinge We might also open migration branch on libdiffpy and pyobjcryst so that @SYMSCAE and @joeseaer would work on that.

Migration work in those repos is on migration-nano branches. I am not sure about pyobjcryst but we can check. Please coordinate with earlier work fine by @SYMSCAE and others (I don't remember exactly)