This commit better defines how we set states in resultNormal,
resultAlerting, resultError and resultNoData. It changes the existing
code to call methods such as SetAlerting, SetPending, SetNormal,
SetError and NoData instead of assigning values to each individual field
whenever the state is changed. This should make it easier to understand
what fields should be set for which states and avoid cases where states are
missing, or have additional unexpected fields.