cleanup environment.yml
cleanup environment.yml

This commit removes the fastqc specific dependencies which should be resolved upstream since
https://github.com/bioconda/bioconda-recipes/pull/12616 was merged

Additionally it fixes the following:

* significantly speeds up the creation of conda environments
* with conda >4.6.7 building the environment failed with
`UnsatisfiableError: The following specifications were found to be in conflict:
  - anaconda::font-ttf-dejavu-sans-mono=2.37
Use "conda search <package> --info" to see the dependencies for each package.`

ewels/NGI-MethylSeq,ewels/NGI-MethylSeq,ewels/NGI-MethylSeq