Implement sort.Interface for Probes
Implement sort.Interface for Probes

The default ("ascending") sort order gives the natural order that's
likely to be most useful when ordering Probes, i.e. with the ones
requiring attention (failing a lot, alerting) first.

Implement Equal() for *Probe, Records, Record types.

Also add String() method for *Probe type.

hkjn/prober