Due to the fact that resources can transition between each modes, trying
to track the mode for a resource as a whole in state doesn't work,
because there may be instances with a mode different from the resource
as a whole. This is difficult for core to track, as this metadata being
changed as a side effect from multiple places often causes core to see
the incorrect mode when evaluating instances.
Since core can always determine the correct mode to evaluate from the
configuration, we don't need to interrogate the state to know the mode.
Once core no longer needs to reference EachMode from states, the
resource state can simply be a container for instances, and doesn't need
to try and track the "current" mode.
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