Change sign_in page to Orcid design

[x] Add ORCID branded button or link to sign-in page for orcid option. Examples can be found at: https://members.orcid.org/api/resources/graphics
[x] ORCID will be the only sign in option in sign_in page.
[x] Add the ORCID iD to the page header. Display the iD as per our display guidelines: https://orcid.org/trademark-and-id-display-guidelines
[x] Demo site and dev will continue to use the sandbox environment.
[x] Add text relating to registering for an ORCID sandbox record. Links to articles relating to the Sandbox can be found at: https://support.orcid.org/knowledgebase/articles/895947-why-am-i-not-receiving-messages-from-the-sandbox and https://support.orcid.org/knowledgebase/articles/166623-is-the-sandbox-different-from-the-production-regis

anusharanganathan / data2paper