Basal odb groups should be modifiable

[DLBPointon]

Description of feature

Rich has suggested that due to issues with bacteria and archaea odbs, they can kill the btk results.
--basal-groups {full,minimal} where full would be eukaryota,bacteria,archaea and minimal would be eukaryota.

[muffato]

If we want to make this an option with string values, I'd rather name it --basal_lineages (to mirror --busco_lineages) and ask people to name the exact lineages they want. The default value would eukaryota,bacteria,archaea (=full) and "minimal" could be achieved with eukaryota.