Update home.html

Help text updates.
Help page update

Adding webinar training blog post link
Merge pull request #249 from mozilla/help-updates

Updates to help page text
Update help.js

Adding FAQs, tidying up.
Update signup.html

Updating sign-up language.
Small tweak to fix overly-small signup form on sorry page
Merge pull request #253 from mozilla/faq-updates

Update help.js