Add example pages to Manon documentation

[HeleenSG]

Describe the bug, issue or concern

Add example pages that can be used as a base for a project using Manon.

This could include

• Basic page setup (header, body, footer)
• Examples of common pages (e.g login page, landing page)

[annejan]

Can be based on docs/src/routes/examples/
Uses Svelte Kit
See also: https://github.com/minvws/nl-rdo-manon/tree/main/examples/tutorial