Add BÉPO ergonomic French keyboard

In french, we have an ergonomic layout called "BÉPO", roughly the equivalent of DVORAK in english. I guess there is a non-negligible cross-over between the users of BÉPO and Typewise, since they both are more efficient new things but which need some effort to get used to. One must in either case have a specific mindset.
Plus, it may need only a couple of key switching to get from the AZERTY to the BÉPO.