Feature/Contact Us Form changes [PLAT-966]

[pattisdr]

Purpose

Add a Captcha to the Contact Us Form

❗️ Contact Us/ Contact Thanks pages need to be removed from admin app ❗️ cos.io needs to be registered in the recaptcha admin @icereval ❗️ RECAPTCHA_SITE_KEY, RECAPTCHA_SECRET_KEY, and CONTACT_US_SUBMISSION_URL need to be added to settings on prod. submission url is the Salesforce url for contact us form submission.

Changes

• Pull the Contact Us and Contact thanks page out of the admin app and into a django app
• Put the contact us fields into a Django Form
• Modify Contact Us Form so "Submit" sends a POST request to /contact/ route, which validates recaptcha. If valid, then forwards the form information to salesforce. If invalid, updates error message on Contact Us page.
• Patterned off of https://github.com/CenterForOpenScience/osf.io/pull/6287/files
• captcha added above Submit button

Ticket

https://openscience.atlassian.net/browse/PLAT-966

[icereval]

FYI, I've pre-populated all settings on Heroku

[sloria]

@icereval Can you also add the config vars for staging-cosio?