Tune GCN architecture

[mkviatkovskii]

Blocked by #659 and #628

After we create a couple of useful presets of featurisers, it could be useful to try to improve GCN architecture to achieve better predicting results.

ToDo
Tune various GCN architecture params to achieve better predicting results on ADRA1A using out best preset of featurisers.

Use best params as default.