Add Slack Form

[digitaldrk]

This one is a little involved

• Use this API endpoint it expects a POST: https://w4olv44zw1.execute-api.us-west-2.amazonaws.com/V1/slack-signup
• Might need API keys, ask Derek about that
• Form should send an email at the least maybe other stuff too but email should work for now
• Form validates presence of email
• Empty div or something that accepts and parses server response
• Form does basic validation of email (bonus)

Example format for a response: "{\"ok\":false,\"error\":\"already_in_team\"}"