Add py-lmdb

Created by: ZhukovAlexander

What is this Python project?

• CFFI/native-C bindings for ultra-fast OpenLDAP's LMDB.
• memory mapped B-tree
• Works on pretty much all versions of python

Anyone who agrees with this pull request could vote for it by adding a 👍 to it, and usually, the maintainer will merge it when votes reach 20.