CRUD for elementaty elements

Only deal with CRUDs of entities without links at the moment.

• NCBI Taxonomy
• KEGG
• EggNOG
• Experiment

added Python To Do labels

assigned to @kehillio

changed title from CRUD for EggNOG to CRUD for elementaty elements

changed the description

changed milestone to %All simple CRUDs

added Doing label and removed To Do label

changed the description

marked the checklist item KEGG as completed

mentioned in merge request !5 (merged)

changed the description

marked the checklist item NCBI Taxonomy as completed

marked the checklist item EggNOG as completed

marked the checklist item Experiment as completed

mentioned in commit e1de85c4

closed with merge request !5 (merged)