Adds an ORCID field to the user model.

Includes the official ORCID icon asset, some partial cleanup, a validator, a database migration, and changes to the generators. And removes the redundant social_media_info partial.
Running generators is slow, so if we're concerned about test performance, and if cached stats hasn't already been released, we should combine the two generators.  Perhaps we could have a new install path vs an upgrade path.