Horzontal content overflow in Filestores documentation

[ptheywood]

The Filestores documentation overflows the RTD theme container, on windows less than ~2500px wide due to the ~1600px wide SVG.

Tables on this page also often overflow the content.

---

The SVG would become illegible if scaled down to the container width, so adding a wrapper element with the width set to the parent and horizontal scrolling allowed (overflow-x: auto; or scroll) are probably the best options.

Suggestions on how to make the tables responsive (wrapped text and showing scroll bars if neccesary) in an issue since 2014:

https://github.com/readthedocs/sphinx_rtd_theme/issues/117]