feat: DRY and doc improvements

Per code review suggestions,

* pulling common options out so we don't have repetition (that can get out of sync)
*  simplifying the documentation, since I hadn't realized we used semantic releases

README.md

@@ -15,10 +15,6 @@ You can also add your own custom metrics as an additional argument, or see the c
 
 General Logging service interface is defined in [frontend-platform](https://openedx.github.io/frontend-platform/module-Logging.LoggingService.html).
 
-## Deployment
-
-When you make changes, [draft a new release](https://github.com/edx/frontend-logging/releases) (and, if necessary, change the imported version number in importing packages).
-
 ## Usage
 
 To install frontend-logging into your project::

src/DatadogLoggingService.js

@@ -49,33 +49,30 @@ class DatadogLoggingService extends NewRelicLoggingService {
     }
 
     const datadogVersion = process.env.DATADOG_VERSION || process.env.APP_VERSION || '1.0.0';
-    datadogRum.init({
-      applicationId: process.env.DATADOG_APPLICATION_ID,
-      beforeSend: this.beforeSend,
+    const commonInitOptions = {
       clientToken: process.env.DATADOG_CLIENT_TOKEN,
       site: process.env.DATADOG_SITE || '',
-      service: process.env.DATADOG_SERVICE || '',
       env: process.env.DATADOG_ENV || '',
+      service: process.env.DATADOG_SERVICE || '',
       version: datadogVersion,
+      trackSessionAcrossSubdomains: true,
+      usePartitionedCrossSiteSessionCookie: true,
+    };
+    datadogRum.init({
+      ...commonInitOptions,
+      applicationId: process.env.DATADOG_APPLICATION_ID,
+      beforeSend: this.beforeSend,
       sessionSampleRate: parseInt(process.env.DATADOG_SESSION_SAMPLE_RATE || 0, 10),
       sessionReplaySampleRate: parseInt(process.env.DATADOG_SESSION_REPLAY_SAMPLE_RATE || 0, 10),
       trackUserInteractions: true,
-      trackSessionAcrossSubdomains: true,
-      usePartitionedCrossSiteSessionCookie: true,
       trackResources: true,
       trackLongTasks: true,
       defaultPrivacyLevel: process.env.DATADOG_PRIVACY_LEVEL || 'mask-user-input',
     });
     datadogLogs.init({
-      clientToken: process.env.DATADOG_CLIENT_TOKEN,
-      site: process.env.DATADOG_SITE || '',
-      env: process.env.DATADOG_ENV || '',
+      ...commonInitOptions,
       forwardErrorsToLogs: true,
-      trackSessionAcrossSubdomains: true,
-      usePartitionedCrossSiteSessionCookie: true,
       sessionSampleRate: parseInt(process.env.DATADOG_LOGS_SESSION_SAMPLE_RATE || 0, 10),
-      service: process.env.DATADOG_SERVICE || '',
-      version: datadogVersion,
     });
   }