reconciler: Fix Status JSON marshalling

43587d4 broke JSON marshalling of Status by introducing a separate statusJSON
type and Unmarshal{JSON,YAML} methods, but didn't introduce the Marshal{JSON,YAML}
methods, which caused dictionary key mismatches as Status struct was used to marshal
instead of statusJSON.

Fix this by removing the whole statusJSON construct and add json and yaml tags to Status.
There is no need for filling in the `id` field when unmarshalling Status as this is completely
internal to the reconciler.

Fixes: 43587d4 ("reconciler: Implement tests using scripttest")

Signed-off-by: Jussi Maki <[email protected]>