Add CONTACT_EMAIL and remove references to info@codalab.org

[Didayolo]

Description

• Remove hard-coded references to "info@codalab.org"
• Use DEFAULT_FROM_EMAIL when relevant
• Add CONTACT_EMAIL to .env file
• Remove the hard-coded info@codalab.org from index.html.
• CONTACT_EMAIL uncommented by default in .env_sample
• DEFAULT_FROM_EMAIL is used by default in src/apps/profiles/helpers.py line 18

Issues this PR resolves

• Forgot Password emails won't send because of hardcoded "from_email" #1816

A checklist for hand testing

• Check the contact email visible at the bottom of homepage, 404 page, and other pages.
• Check platform emails:
  • Account activation emails
  • Password reset
  • Competition forum emails
  • Participation request emails
  • Send messages to participants emails
  • User delete emails

Checklist

• Code review by me
• Hand tested by me
• I'm proud of my work
• Code review by reviewer
• Hand tested by reviewer
• CircleCi tests are passing
• Ready to merge

[ihsaan-ullah]

Why is this PR in in-progress?

[Didayolo]

Why is this PR in in-progress?

I think it is mainly because of this TODO: "we should also remove the hard-coded info@codalab.org from index.html. Maybe CONTACT_EMAIL should be uncommented by default in .env_sample"

Also it needs to be checked and tested a bit more.

[ihsaan-ullah]

Everything looks good. I made some small changes and added CONTACT_EMAIL to home page and 404 page. We should test this on codabench test for

• Account activation emails
• Password reset
• Competition forum emails
• Participation request emails
• Send messages to participants emails
• User delete emails

[ihsaan-ullah]

I am closing this because we have merged the duplicate PR #2060. A small remaining update is mentioned in #2082 and will be fixed soon.