Introducing draper
[#51542515] Add links to the ToS and Privacy policy when registering an organization.
[#51542515] Activate register button only when user complies with the ToS and Privacy Policy
[#51542515] Add an `allow_sharing` field to Organization.

- And show a checkbox for it while registering.
[#51542515] Add the letter_opener gem.

- And clean up the Gemfile.
[#51542515] Add a mailer to notify super admins of organizations that allow sharing.
[#51542515] Send mails asynchronously when an organization that allows sharing data is created