docs: add usage analytics gathering guide to aio (#29382)

This guide is to help third party administrators to collect usage analytics
gathering for their own users with their own Google Analytics dashboard. It
is not meant for a generic audience.

PR Close #29382

aio/content/cli/usage-analytics-gathering.md

@@ -0,0 +1,38 @@
+# Gathering Usage Analytics
+Administrators can configure their instances of Angular CLI to share usage analytics with
+third parties. This sharing is separate from and in addition to usage analytics shared
+with Google. It is disabled by default and cannot be enabled at the project level for
+all users. It must be set at the global configuration level for each user to allow
+managed users to opt in and share usage analytics.  
+
+To configure usage analytics sharing, use the `ng config` command to add both the user ID
+and the third-party ID to the user's global Angular CLI configuration. 
+
+- The third-party ID is the tracking identifier of the third-party Google Analytics
+  account. This ID is a string that looks like `UA-123456-12`.
+- You can choose a user ID, or be assigned a random user ID when you run the CLI command.  
+
+Once you have the third-party tracking ID, add it to your global configuration using the  following command:
+
+```
+ng config --global cli.analyticsSharing.tracking UA-123456-12
+```
+
+To add a custom user ID to the global configuration using the following command. This
+should be unique per users to identify unique usage of commands and flags.
+
+```
+ng config --global cli.analyticsSharing.user SOME_USER_NAME
+```
+
+To generate a new random user ID, run the following command:
+
+```
+ng config --global cli.analyticsSharing.user ""
+```
+
+To turn off this feature, run the following command:
+
+```
+ng config --global --remove cli.analyticsSharing
+```

aio/content/navigation.json

@@ -650,6 +650,11 @@
           "title": "Overview",
           "tooltip": "An introduction to the CLI tool, commands, and syntax.",
           "url": "cli"
+        },
+        {
+          "title": "Usage Analytics",
+          "tooltip": "For administrators, guide to gathering usage analytics from your users.",
+          "url": "cli/usage-analytics-gathering"
         }
       ]
     },