Make the existence of a pattern a requirement for adding an Uberon term

[matentzn]

See #2515 for a bit on this, but the key is:

Every term added to Uberon should be linked to a DOSDP pattern. It does not matter whether the DOSDP has a template for logical definitions - the point is that every term belonging to a class of terms, such as Nerves classified by the anatomical structure that is innervated, or Skeleton of Body part, should be modelled in the same way.

Just to get started, I would suggest to create very imperfect YAML files every time one is missing rather than trying to get it perfect and blocking the whole process. But I vote recommend to the Uberon team to vote this to be a requirement to ensure the consistent evolution of the ontology. This is also to ensure that new terms being added are complete, i.e. not missing critical information.