Fission meets OpenTelemetry (#2157)

* add opentracing section and otelCollectorEndpoint
* initialize OTLP exporter
* pkg/controller: changes for context propagation
* pkg/executor: changes for context propagation
* pkg/fetcher: changes for context propagation
* pkg/router: changes for context propagation
* pkg/storagesvc: changes for context propagation
* set no default value for otel collector endpoint
* update readme and add notes to charts
* move common code to pkg/utils/otel
* adding fn and env as attributes
* don't use otelhttp transport for websocket
* URL ignore with common filter UrlsToIgnore

Note: The web socket example does not work when using OTEL HTTP. Here is an issue related to that on open-telemetry/opentelemetry-js-contrib.

Signed-off-by: Gaurav Gahlot <gauravgahlot0107@gmail.com>
Co-authored-by: Sanket Sudake <sanketsudake@gmail.com>

pkg/storagesvc/client/storagesvc_test.go

@@ -95,8 +95,7 @@ func startS3StorageService(endpoint, bucketName, subDir string) {
 	os.Setenv("STORAGE_S3_REGION", minioRegion)
 
 	storage := storagesvc.NewS3Storage()
-	_ = storagesvc.Start(logger, storage, port)
-
+	_ = storagesvc.Start(logger, storage, port, true)
 }
 
 func TestS3StorageService(t *testing.T) {
@@ -213,7 +212,7 @@ func TestLocalStorageService(t *testing.T) {
 	localPath := fmt.Sprintf("/tmp/%v", testID)
 	_ = os.Mkdir(localPath, os.ModePerm)
 	storage := storagesvc.NewLocalStorage(localPath)
-	_ = storagesvc.Start(logger, storage, port)
+	_ = storagesvc.Start(logger, storage, port, true)
 
 	time.Sleep(time.Second)
 	client := MakeClient(fmt.Sprintf("http://localhost:%v/", port))