Thoracic dorsal root ganglion should not be a part of thoracic ganglion

[stappan]

Uberon term

http://purl.obolibrary.org/obo/UBERON_0002835

Bug description
Dorsal root ganglia are not paravertebral/sympathetic ganglia. The thoracic ganglion currently have http://purl.obolibrary.org/obo/UBERON_0002835 as a subclass.
Recommendation:

• remove thoracic dorsal root ganglion as a subclass of thoracic ganglion.
• clarify the name of thoracic ganglion (http://purl.obolibrary.org/obo/UBERON_0002835) to thoracic paravertebral ganglion, since thoracic ganglion would more properly refer to ganglia that are within the thorax, including spinal, prevertebral and paravertebral ganglia