* Move ErrorHandler impl to internal
To avoid the import cycle, the otel/metric package needs to not import
otel. To achieve this, the error handling implementation is moved to the
otel/internal/global package where both can import the needed
functionality.
* Add global metric to go.opentelemetry.io/otel
* Crosslink and update to global metric in otel
* Add changes to changelog
* Set PR number in changelog
* Add global metric unit tests
* Rename MeterProivder() to GetMeterProivder()
* Add TODO to remove nolint comments
