Rename Event.Status to Event.Condition to match v1beta3 agreement

Question - should this be a phase?  Seems like no, since phase implies
defined lifecycle and this field is explicitly not defined.

@lavalamp

Part of #1519 to allow roundtripping to v1beta3
I added a commented out block and a TODO about removing this when parent type assertions are added (was a bit worried about missing an edge case without it)

----- Original Message -----
> > @@ -507,5 +507,35 @@ func init() {
> >  			out.FieldPath = in.FieldPath
> >  			return nil
> >  		},
> > +
> > +		// Event Status -> Condition
> 
> Instead of conv function consider:
> 
> ```
> newer.Scheme.AddStructFieldConversion(string(""), "Status", string(""),
> "Condition")
> newer.Scheme.AddStructFieldConversion(string(""), "Condition", string(""),
> "Status")
> ```
> 
> I'm not 100% sure it's better. I have a change in the pipeline that will
> allow asserting parent type to avoid accidentally making this transformation
> to another type.
> 
> ---
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> https://github.com/GoogleCloudPlatform/kubernetes/pull/2911/files#r21855738