Adds community landing page for PyCon Africa 2025 (#381)

### Description

This landing page will live at:
https://valkey.io/community/pyconafrica2025/ and will direct attendees
to conference materials.
 
### Issues Resolved

n/a

### Check List
- [x] Commits are signed per the DCO using `--signoff`

By submitting this pull request, I confirm that my contribution is made
under the terms of the BSD-3-Clause License.

Signed-off-by: Kyle J. Davis <[email protected]>

Author: stockholmux

content/community/pyconafrica2025.md

@@ -0,0 +1,16 @@
++++
+title = "Welcome PyCon Africa 2025"
+description = "Welcome PyCon Africa 2025"
+template = "community.html"
+page_template = "community.html"
+[extra]
+cards = [
+    { icon = "icon-bulb.svg", title = "Workshop", description = "If you're joining us for 'Introduction to Valkey + Python' you can find the materials and platform by clicking 'Workshop Platform' below.", links = [
+    { url = "/try-valkey/pyconafrica-workshop/", text = "Workshop Platform" }
+  ] },
+]
++++
+
+# Welcome PyCon Africa 2025
+## How to Contribute with us?
+We welcome your involvement in the Valkey community! Here are several ways you can contribute: