Further simplify state variable usage

Avoid unnecessary initial state polling

Simplify construction of gui objects that either don't need juju state or will be immediately refreshing it.

Be more explicit with naming state variables, and check class of state passed to charm
add initial poll back in because PegasusGUI.init_machine needs juju state.

Ideally we'd just move init_machine to the NodeViewMode class that also needs the state, but this is simpler because it's async.
Use correct state var in member func
fix incorrect keyword args to charm init