CMS: Lock down URI (and PURL) RE identifiers using a regex
CMS: Lock down URI (and PURL) RE identifiers using a regex

Lock down RE identifiers of type URI using a regular expression lifted
from the one AngularJS offers for input elements of type url.

Use that regular expression as the basis of an updated one for PURLs.

au-research/ANDS-ResearchVocabularies-Portal,au-research/ANDS-ResearchVocabularies-Portal,au-research/ANDS-ResearchVocabularies-Portal,au-research/ANDS-ResearchVocabularies-Portal