Add a glossary to the documentation

[simonw]

Call it glossary.rst - it can use a definition list something like this:

.. _glossary:

Glossary
========

Term
  A definition of the term.

Another term
  Another definition.

[simonw]

In the future I may write a script which extracts the terms from this document into a separate database table.

[simonw]

Ansible has a good example of a glossary: https://docs.ansible.com/ansible/latest/reference_appendices/glossary.html

[simonw]

Challenge: explain the difference between view as in SQL view, and view as in the code that serves TableView / DatabaseView etc.