[exporter/otlp] split into its own module

This is to address open-telemetry#6195

exporter/otlpexporter/go.mod

@@ -0,0 +1,44 @@
+module go.opentelemetry.io/collector/exporter/otlpexporter
+
+go 1.19
+
+require (
+	github.com/stretchr/testify v1.8.0
+	go.opentelemetry.io/collector v0.61.0
+	go.opentelemetry.io/collector/pdata v0.61.0
+	go.uber.org/atomic v1.10.0
+	google.golang.org/genproto v0.0.0-20220930163606-c98284e70a91
+	google.golang.org/grpc v1.49.0
+	google.golang.org/protobuf v1.28.1
+)
+
+require (
+	github.com/cenkalti/backoff/v4 v4.1.3 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/logr v1.2.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/golang/snappy v0.0.4 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/compress v1.15.10 // indirect
+	github.com/knadh/koanf v1.4.3 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/mostynb/go-grpc-compression v1.1.17 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opencensus.io v0.23.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.36.0 // indirect
+	go.opentelemetry.io/otel v1.10.0 // indirect
+	go.opentelemetry.io/otel/metric v0.32.1 // indirect
+	go.opentelemetry.io/otel/trace v1.10.0 // indirect
+	go.uber.org/multierr v1.8.0 // indirect
+	go.uber.org/zap v1.23.0 // indirect
+	golang.org/x/net v0.0.0-20220909164309-bea034e7d591 // indirect
+	golang.org/x/sys v0.0.0-20220808155132-1c4a2a72c664 // indirect
+	golang.org/x/text v0.3.7 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)