Add Support for Global Traffic Manager (GTM) functionality

[n3mawashi]

Hi,

Is this something that we want this module todo? If so, what's the preferred nomenclature of the providers and types?

F5_gtmpool?

I'm guessing form any architecture standpoint the GTM WIP's would follow a similar pattern to the virtualservers since WIP's can be an array of types (A, AAA, MX, SRV, etc..).

Keen to hear other ideas and comment before I start this work.