Update content.json

Edits on "teach" section of Open Practices -- author names and descriptions fixed, duplicate entities removed, new entities added.
Merge pull request #913 from keyboardkat/patch-18

Fixes Bug 1045719 - Webmaker textbook: Add/edit "teach" entities for Open Practices
Bug 1032795 - Add localisation for Webmaker Mentor Badge
1.1.32
1.1.33