Edits to classification notebook (#489)

* First edits and updates

* More edits and updates

* add more edits and questions

* use datashader shade instead of matplotlib to show the reclassify aggregation

* remove matplotlib descriptions from raw array figure

* remove stack and hillshade steps from the natural breaks section

* Update style, add details

* Minor updates

* add try out section on classification nb

* Update next steps section

Co-authored-by: Gian Castro <giancastrok@gmail.com>

Author: tcmetzger