add links to bot blog posts from the docs site

[davewhiteland]

• add specific details links within the (running) text

We've got good links to the semi-technical blog posts now on http://docs.everypolitician.org/bot.html But we could helpfully be linking to the bot blog by way of explanation within specific text in the docs.

I originally anticipated those links being styled with the wee bot icon (which is currently feasible, with the existing link--epbot class); subject perhaps to designer sign-off (see #17).

This issue was originally ticketed (in a slightly different form) on the wrong repo: everypolitician/everypolitician#405