Upload and update global opengraph image, and create a opengraph desc…

…ription override for homepage (#6696)

**Context:**

This pull request introduces enhancements to the documentation site's
SEO by adding a custom Open Graph image and description for the
homepage. These changes ensure better visibility and presentation when
the site is shared on social platforms or link previews.

**Description of the Change:**
- **New Open Graph Image:** Uploaded `opengraph.png` for consistent
branding across social platforms.
- **Global Open Graph Update:** Updated the global `opengraph` image
source to reference the new image.
- **Homepage Title & Description Override:** Added an [`og:description`
override](https://github.com/wpilibsuite/sphinxext-opengraph?tab=readme-ov-file#per-page-overrides)
in `index.rst` to provide a custom meta `og:description` for the
homepage.

 
**Benefits:**
- Improved SEO

**Possible Drawbacks:**
- N/A

**Related GitHub Issues:**
- N/A

doc/conf.py

@@ -57,7 +57,7 @@
     "site_url": "https://docs.pennylane.ai/",
     "line_color": "#03b2ff",
 }
-ogp_image = "_static/header-tall.png"
+ogp_image = "_static/opengraph.png"
 
 
 # The base URL with a proper language and version.

doc/index.rst

@@ -1,3 +1,5 @@
+:og:description: Accelerate your adoption of PennyLane! Find clear, concise, accessible, and current information that will help you understand, use, and troubleshoot issues.
+
 PennyLane Documentation
 =======================
 

doc/releases/changelog-dev.md

@@ -467,6 +467,9 @@ same information.
 * Add a warning message to Gradients and training documentation about ComplexWarnings.
   [(#6543)](https://github.com/PennyLaneAI/pennylane/pull/6543)
 
+* Added `opengraph.png` asset and configured `opengraph` metadata image. Overrode the documentation landing page `meta-description`.
+  [(#6696)](https://github.com/PennyLaneAI/pennylane/pull/6696)
+
 * Updated the documentation of `QSVT` to include examples for different block encodings.
   [(#6673)](https://github.com/PennyLaneAI/pennylane/pull/6673)
 
@@ -516,6 +519,7 @@ Pietropaolo Frisoni,
 Austin Huang,
 Korbinian Kottmann,
 Christina Lee,
+Alan Martin,
 William Maxwell,
 Andrija Paurevic,
 Justin Pickering,