Convert Help page to Markdown for easier editing and contributions

[fabd]

The Help page is currently a plain html template with some symfony stuff.

Breakdown

• It needs to be converted to Markdown so it is easier to edit
• Render the .md file with Parsedown or another good Markdown library with few dependencies
• Add it to the public repo for contributions (eg. typos & translations)

Fixes

• Merge this? Attributes don't parse. Misc bugfix and improved attribute parsing erusev/parsedown-extra#101 NOT NEEDED ATM.
  Fork: https://github.com/kael-shipman/parsedown-extra/commits/master

Extensions

• Map internal URIs, perhaps "@module/index" symfony router syntax. (or maybe relative links are already supported?) Should work

Looking into Parsedown atm.

[fabd]

Fixed by 193b8c0

Ugh.. it's a good thing this isn't fully OS yet because I'm such a Git newb 😓