docs: agents tutorial (#8961)

* minimal-working-code

* remove-old-files-and-add-new-content

* cleanup

* more-content

* use-directory-instead-of-sql

* sidebars

* style-cleanup

* slug

* directory

* tools-port

* use-ts-client

* code-review

* next-steps

* Apply suggestions from code review

Co-authored-by: April I. Murphy <36110273+aimurphy@users.noreply.github.com>

* docs-review

* Update sidebars.js

* fix-some-anchors

* docs-review

---------

Co-authored-by: Edwin Jose <edwin.jose@datastax.com>
Co-authored-by: April I. Murphy <36110273+aimurphy@users.noreply.github.com>

docs/sidebars.js

@@ -26,6 +26,7 @@ module.exports = {
           items: [
             "Tutorials/chat-with-rag",
             "Tutorials/chat-with-files",
+            "Tutorials/agent",
           ],
         },
       ],