Make the Get Involved page more inviting and actionable

[elipousson]

The Get Involved page is incomplete and confusing. Here is how I think it should be improved:

• Remove information on Trello (we are not using the board at the moment and it may confuse people)
• Add at least one image
• Add a clear call to action (e.g. link to contributor guidelines, link to setup GitHub account, link to help-wanted issue list)
• Add a contact form to contact me with interest in volunteering

[elipousson]

I just updated the Get Involved page with a section for contributing online via GitHub and a section for contributing via our upcoming workshops. I think the page still needs a better call-to-action and I'd like to make the section on contributing online a bit more accessible for anyone who is completely unfamiliar with using GitHub.

I also need to work on a standard set of contribution guidelines that I can use for both this main site and for any separate course repositories—I'll put those in a separate issue.

[todrobbins]

Looking good! I think I'll make a comp of the page to address the call to action and contact form.