AthenaConfiguration: sort structured print in confTool to aid comparison
I've found it useful to be able to compare old-style and CA configuration via the structured print option of confTool, but for this to work the output needs to be sorted.
This MR has no impact on any production output changes - it's just a minor change to a fairly niche helper tool, but since configuration changes are going into 22.0 it might be useful to have this here.