Added a Provider entry to patient demographics.
-Since the current provider entry in demographics was
being used both as referring provider and main
provider in the codebase, did the following:
-Made the current providerID entry only for the main
provider.
-Created a new ref_providerID entry for referring provider
-For upgraders, copied the providerID info to the
ref_providerID field to ensure previous fx is not broken.
-In codebase, elements that were using providerID to collect
the referring provider now map to ref_providerID.