New format: BGEN #417
Description
We would like to support conversion of BGEN data to VCZ.
Sgkit has a [read_bgen]https://sgkit-dev.github.io/sgkit/latest/generated/sgkit.io.bgen.read_bgen.html) function so it should be a fairly straightforward process of porting the sgkit code over here, and hopefully should be reasonably similar to our plink conversion code.
Following sgkit we'd probably use cbgen to access the data, but we could definitely use some other library if that made sense.