Add community notebooks to the website (#2913)

Summary:
We have a few notebooks under notebooks_community that were contributed by the BoTorch community. It's time to showcase these on the website!

Pull Request resolved: #2913

Test Plan:
https://github.com/user-attachments/assets/c8463b87-5979-4550-8714-e9248382436e

With changes to make it only show when the content exists:

https://github.com/user-attachments/assets/bf716e80-3154-4965-b35a-ebcaf7a96ceb

Reviewed By: Balandat

Differential Revision: D77872826

Pulled By: saitcakmak

fbshipit-source-id: 0d4cfb62328d7438021623d750c9db03c3b99691

Author: saitcakmak

.gitignore

@@ -102,6 +102,10 @@ website/static/files/
 docs/tutorials/*
 !docs/tutorials/index.mdx
 
+# Generated for community noteboooks
+docs/notebooks_community/*
+!docs/notebooks_community/index.mdx
+
 ## Generated for Sphinx
 website/pages/api/
 website/static/js/*

docs/notebooks_community/index.mdx

@@ -0,0 +1,8 @@
+---
+title: Community Notebooks
+---
+This section of the website displays a list of notebooks contributed and maintained
+by the BoTorch community. These notebooks often showcase recent methods from the
+literature that are implemented using BoTorch.
+
+Interested in contributing? Check out our [contributing guide](https://github.com/pytorch/botorch/blob/main/CONTRIBUTING.md#community-contributions-beta)!

notebooks_community/README.md

@@ -8,3 +8,5 @@ Each notebook should include a timestamp of last update, as well as the version
 of BoTorch that was used during execution. Each notebook should also list the
 GitHub handle of its contributors, who may be asked for help in maintaining &
 updating the notebook against future versions for BoTorch and dependencies.
+
+The notebooks are parsed and included in the BoTorch website.