Remove enable_default_view option

[aabmass]

The enable_default_view behavior should be accomplished with views as described in open-telemetry/opentelemetry-specification#2417

SDK SHOULD enable the instrument using the default aggregation and temporality. Users can configure match-all Views using Drop aggregation to disable instruments by default.

E.g.

MeterProvider(
  views=[
    View(instrument_name="*", aggregation=DropAggregation()),
    View(instrument_name="<instrument1 to turn on>"),
    View(instrument_name="<instrument2 to turn on>"),
  ],
  ...
)