Elavon has a new Hosted Payments Page for Offsite Redirect method, old one is unsupported

Problem/Motivation

I contacted Elavon support for another issue and gave them a screenshot of the form I get by using the "Elavon (Off-site redirect)" payment gateway plugin provided by this module. Here is part of their reply:

What integration method is the merchant using? That looks like our old Hosted Payments Page which is no longer supported, you would need to setup the HPP inside of Nextgen if this is the integration method.

Proposed resolution

I think the module needs to add a new plugin for the "Nextgen integration method". Since the old one is still in use by many and there is some setup required in order to use the new method, I think the old plugin should remain to allow people to switch when they can/want to.

I will spend some time on this and if the switch isn't too complicated, I will try to provide a patch.