Add normalize_vcf and remove_homref_sites processes

[sdhutchins]

This PR addresses #18 by adding a conda environment and adding the necessary precursor steps before extractFromVCF that use bcftools to prepare the input vcf file.

Changes

• Create conda environment config
• Create normalize_vcfprocess
• Create remove_homref_sites process

What to test

• [x] Test creation of all files in the scratch directory
• [x] Test workflow processes

Instructions

module load Anaconda3
module load Java/13.0.2
nextflow run pipeline.nf -with-conda true