Switch from LMDB to libmdbx

[erthink]

https://github.com/leo-yuriev/libmdbx#libmdbx

[mykmelez]

Hi @leo-yuriev, is there something in particular you think we should consider about libmdbx?

[erthink]

Hi, @mykmelez .
I was taking a break to tidy up some important things, before replying and wasting your time.
In short, I suggest you consider using libmdbx instead of LMDB.

[Kerollmops]

Here is a basic version of the rust mdbx bindings (which is a simple fork of the fork of mozilla).

[erthink]

FYI.

Erigon (one of the most efficient frontiers for Ethereum) recently switched from LMDB to MDBX.
AFAIK, there was no single reason, but because are a set of MDBX's improvements over LMDB.

Regards.