Support UDP transfer

[jeppenodgaard]

Add UDP transport support. This is supported by the Go mcumgr-client.
Related BLE support issue.

[bperseghetti]

@jeppenodgaard was curious if you know of any work already going on toward supporting UDP for this.

[jeppenodgaard]

@jeppenodgaard was curious if you know of any work already going on toward supporting UDP for this.

Not that I am aware of.

[Frank-Buss]

I'm not working on it either. But would be cool to have such a feature.