Move content for developers to a dedicated page

[BoHristova]

What would you like to be added:
Create a dedicated page for contributors (similarly to https://kubectl.docs.kubernetes.io/contributing/).

The page should be accessible via a button in the top‑level navigation (similar to the Blog section) and should have its own landing page and sidebar navigation.

The page will contain:

• Content for the “Developer” persona
• Content from the current Contribute section .

Why is this needed:

• Makes contributing easier by giving developers a single place to find all contribution-related content
• Reduces clutter in the general documentation