Add EfficientIP plugin

[jamiekowalczik]

This is my first pull request, I apologize if I am doing it incorrectly. As recently previously stated in your Issues by someone else, the quality and documentation you have put into this project is truly amazing.

[rmbolger]

Just a heads up. I reached out to EfficientIP to see if I could procure some sort of trial/demo. Still waiting on a response.

[rmbolger]

Adding a quick link to #486 which this PR would address.

[jamiekowalczik]

Thank you for contacting them. I hope they see the value in it.

[jamiekowalczik]

I created a support ticket to request approval of your inquiry. Maybe if others interested do the same, that will help. Thanks again for all of your great work on Posh-ACME.

[rmbolger]

I've still heard nothing but crickets from EfficientIP about a demo/trial. I'm tempted to reach out from my work address, but that probably wouldn't happen until the new year.

Might you have access to installation media that could somehow find its way to me? I don't know how licensing works, so it may be pointless if it doesn't work without some sort of keys though. We run Infoblox at work which uses 60-day trial licenses by default. So I'm hoping there's something like that baked in.