Better BibTeX citekeys

[g-simmons]

Adds support for Better BibTeX citekeys as discussed in #67.

Changes:

• add hostname, port, better_bibtex args to ZoteroDB init
• Make _get_citation_key a method of ZoteroDB
• If ZoteroDB is initialized with better_bibtex=True, call the Better BibTeX RPC endpoint via the Zotero Connector Integration
• Add requests to setup.py requirements
• If this errors, fall back to the default citation keys with a warning
• If better_bibtex=False, use the default citekey format

[jamesbraza]

Hi @g-simmons thank you for this PR. We just released v5 today which changes basically the whole repo.

If you are still interested, please rebase this PR atop the current main branch. Also, can you move from requests to httpx

[g-simmons]

@jamesbraza thanks for the info. I probably won't be able to rebase this any time soon (other time commitments) :/