GO Enrichment Analysis

[JakaKokosar]

Current gene ontology enrichment runs quite slow and consumes a lot of system memory.

The proposal is, that we use gotea module from Genialis repository: https://github.com/genialis/gotea

Usage: https://github.com/genialis/resolwe-bio/blob/master/resolwe_bio/tools/goea.py#L64

This change will introduce a major redesign in current GO module and OWGOBrowser widget.