Add fields to the sign up page for GitHub and ORCID IDs

[jvendetti]

Add two optional fields to the new account creation page that would allow users to enter their GitHub ID and/or their ORCID iD.

See ncbo/ontologies_linked_data#160 for a more detailed explanation of why these fields are necessary. Attribution of ontology change requests issued from BioPortal is a highly desirable feature for ontology curators.

[jvendetti]

After further research, best practice in UX design calls for as few fields as possible on account creation pages for the best conversion rates. The fields for adding / editing GitHub usernames and ORCID iDs have been placed on the edit account page instead. End users can follow these steps to add this data in BioPortal:

1. Register for an account
2. Once logged in, navigate to the Account Settings page (accessible from a menu in the top-right)
3. Click the "Edit account" button
4. On the resulting form, optionally add a GitHub username and/or ORCID iD
5. Click the Update button to save the changes

This functionality was implemented as part of pull request #321, and available in the production environment as of the 6.18.0 release.