New example glm ordinal features (pymc-devs#717)

* + added new notebook GLM-ordinal-features.ipynb
+ already complete and created in another env

* Created using Colab

* minor updates for latest seaborn

* Tweaks for collab and included authors

* added header

* + added new reference article and online
+ cited inside Notebook
+ adjusted errata

* + ran black again...

* + rep Burkner as B{\"u}rkner

* + maybe fixed readthedocs complaint pybtex.database.InvalidNameString: Too many commas in 'B{\\"u}rkner, P., & Charpentier, E.'

* + ran black-jupyter, let's see

* + another run of black-jupyter

* + installed local pymc_examples env
+ ran pre-commit in full
+ autocreated *.myst file

* + update tags

* + possibly persuaded the precommits to all pass

* + rerun on colab to confirm all good post new pre-commit process

* + okay, reran in colab again... lets see if this passes

* + added (again) the myst.md

* + minor updates post review
+ new work to positively include a coeff in mdlb for d450 = c4

* + reran precommit and readded myst.md

* + rerun localyl e2e

* + added myst.md again

* + reran again to ensure cell execution order even for markdown cells

* + reran again again to ensure order

* + minor update: forced addtional level c4 into d450 categorical feature
+ fixed a couple of typos

* + changed rating to intermediate

Author: jonsedar