Log Message:
biology/minimap2: install minimap2 program instead of python binding

The distfile for minimap2 includes two different components: (i) the
minimap2 sequence mapping program itself, and (ii) a python binding
generally referred to as mappy.  The initial version of this package
included only the python binding.  However, it is more appropriate
that the minimap2 package should contain the program of the same name,
and a new package be created with the name mappy for the python
binding.  Splitting these into two packages makes sense, because this
allows users to install the minimap2 package without python
dependencies.