Using orjson instead of default json library

[ff137]

Good day,

Just a quick question, because it doesn't appear to have been suggested here before:
Have you considered replacing the default json library with orjson? It boasts 10-50x faster speeds in some instances.

Just asking to gauge sentiment on using orjson instead, and it's maybe something I can help contribute.

[nicholascar]

These sorts of suggestions - to use faster versions of packages - do come up from time-to-time. The issue here is "pure python". orjson is a rust-based thing, right? We do need to maintain a pure Python implementation.

A PR to allow an install option for rdflib with orjson instead of json would be welcome!