[WFCORE-250] Use the log file resources and streaming API to download log files

Also removed the `View with CLI` button as it seemed rather difficult to get it to work. The operation is available on each resource.

@ssilvert could you give this a review please? If it's simple enough to add the View with CLI button back and I'm just being stupid let me know. We essentially need to execute `/subsystem=logging/log-file=server.log:read-log-file)`.
The server can send out-of-band messages to the client while it executes. The intent was for progress reports, that kind of thing.

AFAIK, it's currently never used by the server. It was used in the 7.0.0.Alpha1 days to send messages about how an operation was rolling out across the domain, but when we moved to detyped API / DMR we put that on the shelf as a "nice to have" as we had no time to do anything with it.

BTW I haven't looked at the code that has generated these comments, so please don't interpret my answer as being in any way about this patch. :)