Add SQL migration for usercache
Add SQL migration for usercache

Working on #670

wheldom01/privacyidea,privacyidea/privacyidea,wheldom01/privacyidea,jh23453/privacyidea,privacyidea/privacyidea,wheldom01/privacyidea,privacyidea/privacyidea,wheldom01/privacyidea,jh23453/privacyidea,jh23453/privacyidea,jh23453/privacyidea,privacyidea/privacyidea,wheldom01/privacyidea,jh23453/privacyidea,privacyidea/privacyidea,jh23453/privacyidea,wheldom01/privacyidea,privacyidea/privacyidea