[ServiceBus] Support websockets

[annatisch]

This is also needed for EventHubs. Blocked by support needed in uAMQP.

[dennispg]

What is the update on this? Is my pull request redundant with upcoming updates , or can it be merged as a minor update to the current version of the library at least?

[KieranBrantnerMagee]

Hey Dennis,

Apt timing, as we're very literally on a call discussing this right now. (There was some back and forth under whether this would be coming in via our next major version, but we've settled on looking into this now.)

Thanks in advance for all your patience thus far re: the delay to our engaging in this. Expect PR comments shortly :)

[dennispg]

Thanks for the update, I'll work through all the comments this weekend!