Improve DynamicTable documentation

[rly]

Motivation

Added a new tutorial on DynamicTable and renamed the old one to be a "how-to guide", inspired by the Divio documentation system: https://documentation.divio.com/

A tutorial should be learning-oriented. The point is to get the user started learning by doing, not serve as a manual or reference. It should focus on concrete steps, not abstract concepts. And it should provide the minimum necessary explanation. Other details can be provided in a how-to guide or reference.

Also added documentation on the options for DynamicTable.get and DynamicTable.to_dataframe.

ref: #579 (comment)

Checklist

• Did you update CHANGELOG.md with your changes?
• Have you checked our Contributing document?
• Have you ensured the PR clearly describes the problem and the solution?
• Is your contribution compliant with our coding style? This can be checked running flake8 from the source directory.
• Have you checked to ensure that there aren't other open Pull Requests for the same change?
• Have you included the relevant issue number using "Fix #XXX" notation where XXX is the issue number? By including "Fix #XXX" you allow GitHub to close issue #XXX when the PR is merged.

[oruebel]

I would change this to ".. note::" instead since you are not recommending this behavior. It would also be useful to indicate briefly why this is not recommended.

[rly]

Done. Thanks.