Identify Contact Submit Action should lowercase the field value

[markgibbons25]

The IdentifyContactAction doesn't lowercase the field value chosen as the contact identifier. I think that it should, or at least an option to enable that should exist. Most people will be using it on email address, so since contact identifiers are case sensitive it is possible to create duplicates.

Another related issue is that the identifier source is hardcoded to "email", it should be allowed to be manually entered on the submit action.