Initial implementation of an extension-based default analytics API

Signed-off-by: Eric Peterson <ericpeterson@spotify.com>

docs/plugins/analytics.md

@@ -101,6 +101,24 @@ export const apis: AnyApiFactory[] = [
     },
   }),
 ];
+
+// Or, when building for the new frontend system:
+import { AnalyticsBlueprint } from '@backstage/frontend-plugin-api';
+
+export const acmeAnalyticsImplementation = AnalyticsBlueprint.make({
+  name: 'acme',
+  params: define =>
+    define({
+      deps: {},
+      factory() {
+        return {
+          captureEvent: event => {
+            window._AcmeAnalyticsQ.push(event);
+          },
+        };
+      },
+    }),
+});
 ```
 
 In reality, you would likely want to encapsulate instantiation logic and pull
@@ -140,6 +158,18 @@ export const apis: AnyApiFactory[] = [
     factory: ({ configApi }) => AcmeAnalytics.fromConfig(configApi),
   }),
 ];
+
+// Or, when building for the new frontend system:
+import { AnalyticsBlueprint } from '@backstage/frontend-plugin-api';
+
+export const acmeAnalyticsImplementation = AnalyticsBlueprint.make({
+  name: 'acme',
+  params: define =>
+    define({
+      deps: { configApi: configApiRef },
+      factory: ({ configApi }) => AcmeAnalytics.fromConfig(configApi),
+    }),
+});
 ```
 
 If you are integrating with an analytics service (as opposed to an internal