[DOCS] Add docs for 8.0 Upgrade Assistant (elastic#28138)

docs/management/upgrade-assistant/index.asciidoc

@@ -1,70 +1,14 @@
-[role="xpack"]
-[[xpack-upgrade-assistant]]
+[[upgrade-assistant]]
 == Upgrade Assistant
 
-The Upgrade Assistant helps you prepare to upgrade from Elasticsearch 5.x to
-Elasticsearch 6.0. It identifies deprecated settings, simplifies reindexing
-your pre-5.x indices, and upgrades the internal indices used by Kibana and
-X-Pack to the format required in 6.0.
+The Upgrade Assistant helps you prepare for your upgrade to {es} 8.0. 
+To access the assistant, go to *Management > 8.0 Upgrade Assistant*. 
 
-To access the Upgrade Assistant, go to **Management** and click the **Upgrade
-Assistant** link in the Elasticsearch section.
+The assistant identifies the deprecated settings in your cluster and indices 
+and guides you through the process of resolving issues, including reindexing. 
 
-[float]
-[[cluster-checkup]]
-=== Cluster Checkup
+Before upgrading to Elasticsearch 8.0, make sure that you are using the final 
+7.x minor release to see the most up-to-date deprecation issues. 
 
-The first step in preparing to upgrade is to identify any deprecated settings
-or features you are using. The Cluster Checkup runs a series of checks
-against your cluster and indices and generates a report identifying
-any issues that you need to resolve.
-
-To run the Cluster Checkup, go to the **Cluster Checkup** tab in the
-Upgrade Assistant. Issues that **must** be resolved before you can upgrade to
-Elasticsearch 6.0 appear in red as errors.
-
-If the checkup finds indices that need to be reindexed, you can
-manage that process with the Reindex Helper. You can also manually reindex or
-simply delete old indices if you are sure you no longer need them.
-
-[float]
-[[reindex-helper]]
-=== Reindex Helper
-If you have indices created in 2.x, you must reindex them before
-upgrading to Elasticsearch 6.0. In addition, the internal Kibana and X-Pack
-indices must be reindexed to upgrade them to the format required in 6.0.
-
-To reindex indices with the Reindex Helper:
-
-. **Back up your indices using {ref}/modules-snapshots.html[Snapshot and Restore].**
-. Go to the **Reindex Helper** tab in the Upgrade Assistant.
-. Click the **Reindex** button to reindex an index.
-. Monitor the reindex task that is kicked off.
-
-You can run any number of reindex tasks simultaneously. The processing status
-is displayed for each index. You can stop a task by clicking **Cancel**. If
-any step in the reindex process fails, you can reset the index by clicking
-**Reset**.
-
-You can also click **Refresh Indices** to remove any indices that have been
-successfully reindexed from the list.
-
-Reindexing tasks continue to run when you leave the Reindex Helper. When you
-come back, click **Refresh Indices** to get the latest status of your indices.
-
-NOTE: When you come back to the Reindex Helper, it shows any tasks that are
-still running. You can cancel those tasks if you need to, but you won't have
-access to the task progress and are blocked from resetting indices that fail
-reindexing. This is because the index might have been modified outside of
-your Kibana instance.
-
-[float]
-[[toggle-deprecation-logger]]
-=== Toggle Deprecation Logger
-
-To see the current deprecation logging status, go to the **Toggle Deprecation
-Logging** tab in the Upgrade Assistant. Deprecation Logging is enabled by
-default from Elasticsearch 5.x onward. If you have disabled deprecation logging, you
-can click **Toggle Deprecation Logging** to re-enable it. This logs any
-deprecated actions to your log directory so you can see what changes you need
-to make to your code before upgrading.
+[role="screenshot"]
+image::images/management-upgrade-assistant-8.0.png[]