First release of nf-core/metapep

Main functionality:

• Download proteins for input type taxa from Entrez.
• Predict proteins for input type assembly or bins using Prodigal.
• Generate peptides from proteins.
• Split peptide files into chunks for parallel prediction and report stats.
• Predict epitopes for given alleles and peptides using SYFPEITHI, MHCflurry or MHCnuggets.
• Downstream visualizations between conditions (different microbiomes assemblies, bins, taxids or same input class with different weights) given within samplesheet
• Summarize workflow using MultiQC
• Relational datamodel to handle large amounts of data Tables defined within model
• Additional subworkflow to fetch possible model and peptide lengths for the prediction tools