Make the stdout exporter a package (#963)

* Make the stdout exporter its own package

Follow the pattern of the other exporters.

* Update dependabot with stdout exporter

* Add replace directives for stdout exporter

* Remove outdated example test from metric SDK

* go mod tidy

* Update othttp example test

Remove unused stdout exporter.

* Remove tests in API that depend on stdout exporter

The global package does not need to be validated with the SDK. A more
properly constructed end-to-end integration test should be built if this
is actually needed.

* Add replace clause for otel in stdout go.mod

sdk/metric/example_test.go

@@ -1,55 +0,0 @@
-// Copyright The OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package metric_test
-
-import (
-	"bytes"
-	"context"
-	"fmt"
-
-	"go.opentelemetry.io/otel/api/kv"
-
-	"go.opentelemetry.io/otel/api/metric"
-	"go.opentelemetry.io/otel/exporters/stdout"
-)
-
-func ExampleNew() {
-	buf := bytes.Buffer{}
-	_, pusher, err := stdout.NewExportPipeline([]stdout.Option{
-		// Defaults to STDOUT.
-		stdout.WithWriter(&buf),
-		stdout.WithPrettyPrint(),
-		stdout.WithoutTimestamps(), // This makes the output deterministic
-	}, nil)
-	if err != nil {
-		panic(fmt.Sprintln("Could not initialize stdout exporter:", err))
-	}
-
-	meter := metric.Must(pusher.Provider().Meter("example"))
-	counter := meter.NewInt64Counter("a.counter")
-	counter.Add(context.Background(), 100, kv.String("key", "value"))
-
-	// Flush everything
-	pusher.Stop()
-
-	fmt.Println(buf.String())
-	// Output:
-	// [
-	// 	{
-	// 		"Name": "a.counter{instrumentation.name=example,key=value}",
-	// 		"Sum": 100
-	// 	}
-	// ]
-}