Docs: Settings updates at runtime (#34169) (#34892)

* Docs: Settings updates on runtime docs skeleton

* Docs: Settings HTTP API

* Docs: Minor changes on settings updates at runtime docs

* Docs: Settings updates at runtime description

* Docs: Minor fix

* Docs: Move PUT /api/admin/settings docs into Admin API page

* Docs: Added longer explanation into 'Settings updates at runtime' page

* Apply suggestions from code review

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
Co-authored-by: Leonard Gram <leo@xlson.com>

* Docs: Include order of precedence description at settings updates page

* Update docs/sources/http_api/admin.md

* Docs: Add link to main configuration page from Settings updates at runtime

* Apply suggestions from code review

Co-authored-by: Mitch Seaman <mjseaman@users.noreply.github.com>

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
Co-authored-by: Leonard Gram <leo@xlson.com>
Co-authored-by: Mitch Seaman <mjseaman@users.noreply.github.com>
(cherry picked from commit 886f6fc55b)

docs/sources/http_api/admin.md

@@ -11,7 +11,7 @@ The Admin HTTP API does not currently work with an API Token. API Tokens are cur
 the permission of server admin, only users can be given that permission. So in order to use these API calls you will have to use Basic Auth and the Grafana user
 must have the Grafana Admin permission. (The default admin user is called `admin` and has permission to use this API.)
 
-## Settings
+## Fetch settings
 
 `GET /api/admin/settings`
 
@@ -169,6 +169,57 @@ Content-Type: application/json
   }
 }
 ```
+
+## Update settings
+
+`PUT /api/admin/settings`
+
+> **Note:** Available in Grafana Enterprise v8.0+.
+
+Updates / removes and reloads database settings. You must provide either `updates`, `removals` or both.
+
+This endpoint only supports changes to `auth.saml` configuration.
+
+**Example request:**
+
+```http
+PUT /api/admin/settings
+Accept: application/json
+Content-Type: application/json
+Authorization: Bearer eyJrIjoiT0tTcG1pUlY2RnVKZTFVaDFsNFZXdE9ZWmNrMkZYbk
+
+{
+  "updates": {
+    "auth.saml": {
+      "enabled": "true"
+    }
+  },
+  "removals": {
+    "auth.saml": ["single_logout"]
+  },
+}
+```
+
+**Example response:**
+
+```http
+HTTP/1.1 200 OK
+Content-Type: application/json
+Content-Length: 32
+
+{
+  "message":"Settings updated"
+}
+```
+
+Status codes:
+
+- **200** - OK
+- **400** - Bad Request
+- **401** - Unauthorized
+- **403** - Forbidden
+- **500** - Internal Server Error
+
 ## Grafana Stats
 
 `GET /api/admin/stats`