* 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
Comment should be complete sentences outside of lists with sentence
fragments. This adds the godot linter to check these complete sentences
end with punctuation. If they do not, running fix will append a period.
* Add benchmarks for error handler
* All multiple global ErrorHandler sets
* Use ioutil instead of io for Discard
* Add changes to changelog
* Add unit tests for delegation
* Move global code to toplevel package
* Move version function to toplevel package
* Update changelog
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>