Simplify this repo into the "engine" and pass api responsibility to https://github.com/NIH-CARD/brain_label8r

[ergonyc]

We will also have a separate github for composing / managing the taxonomies and methods for assigning "ground truth" cell type labels:

engine

https://github.com/ergonyc/labelator

• module is named lbl8r
• tool / repo is called labelator

taxonomy

https://github.com/NIH-CARD/brain_label8r

• maybe change repo name to brain-lbl8r? or brain-labelator

api

https://github.com/NIH-CARD/brain-taxonomy