Fix for the crash of flye_medaka_workflow when running the POLISH workflow

[rc-reding]

In its current state, the workflow crashes when going through POLISH. Medaka tries to call python, which expects to be in the bin/ directory of the conda environment. But there is no python binary or link in bin/. Adding python to environment.yml fixes this problem.

Medaka also needs the python module ont_fast5_api, which is not currently listed as a dependency. So envs\medaka.yml now includes ont-fast5-api. Note that if python is added to envs\medaka.yml, medaka is still unable to find ont_fast_api somehow. If python is added to environment.yml, the module loads.

With these two changes, the nextflow command listed in the onboarding tutorial works just fine.