Please add support for creating service bus topics and subscriptions

[bunceg]

NB: As requested, moved from old repository here:
Azure/azure-sdk-tools#2936 (comment)

To create topics and subscriptions is a manual step which is laborious and error prone. These processes are ideal for powershell scripting and as, service bus is significant part of the Azure offering, these should be added to to the suite of scripts.

[markcowl]

@matt-gibbs Please assign appropriately to the servicebus team

[crpietschmann]

What's the status on this? It doesn't look like it's been worked on yet. I'm thinking about contributing a PR in this area.