<Enterprise Docs> Add instructions to upload license via UI (#28067)

* Add UI license upload option, reformat Enterprise license activation section

Added the option to upload a license file through the Server Admin UI, and did a little reformatting to make license activation look more like a process.

* Headers not bold, hyphens not asterisks

docs/sources/enterprise/_index.md

@@ -71,11 +71,25 @@ With a Grafana Enterprise license, you get access to premium plugins, including:
 
 To purchase or obtain a trial license contact the Grafana Labs [Sales Team](https://grafana.com/contact?about=support&topic=Grafana%20Enterprise).
 
-### License file management
+## Activate an Enterprise license
 
-To download your Grafana Enterprise license log in to your [Grafana Cloud Account](https://grafana.com) and go to your **Org Profile**. In the side menu there is a section for Grafana Enterprise licenses. At the bottom of the license details page there is **Download Token** link that will download the *license.jwt* file containing your license.
+Follow these steps to activate your Grafana Enterprise license:
 
-Place the *license.jwt* file in Grafana's data folder. This is usually located at `/var/lib/grafana` on Linux systems.
+### 1. Download your license file
+
+   To download your Grafana Enterprise license, log in to your [Grafana Cloud Account](https://grafana.com) and go to your **Org Profile**. In the side menu there is a section for Grafana Enterprise licenses. At the bottom of the license details page there is **Download Token** link that will download the *license.jwt* file containing your license.
+
+### 2. Add your license file to a Grafana instance
+
+   There are two different ways to add the license file to a Grafana instance:
+
+   - Option 1: Upload the license file through the Grafana Server Administrator page
+
+     Sign in as a Server Administrator. Navigate to **Server Admin > Upgrade** within Grafana, click on **Upload license token file**, select your license file, and upload it.
+
+   - Option 2: Place the *license.jwt* file in Grafana's data folder. 
+   
+     This is usually located at `/var/lib/grafana` on Linux systems.
 
      You can also configure a custom location for the license file via the ini setting:
 
@@ -86,7 +100,7 @@ license_path = /company/secrets/license.jwt
 
      This setting can also be set with an environment variable, which is useful if you're running Grafana with Docker and have a custom volume where you have placed the license file. In this case, set the environment variable `GF_ENTERPRISE_LICENSE_PATH` to point to the location of your license file.
 
-### Root URL
+### 3. Ensure that the license file's root url matches the root_url configuration option
 
    Update the [`root_url`](../administration/configuration/#root-url) in your configuration. It should be the URL that users type in their browsers to access the frontend, not the node hostname(s).