Meet Apache Website requirements

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Description of Bug

We do not meet several requirements Apache has for top-level project websites. The full list can be seen here: https://whimsy.apache.org/site/project/lucenenet

This includes the original bug report below, about missing images. All external resources should be hosted on Apache servers.

### Original Bug Report

The "Popular Books" images on the homepage are broken, seemingly as a result of a CSP change at Amazon.

### Expected Behavior

The images appear (or the section is otherwise corrected, perhaps with text links)

### Steps To Reproduce

Visit the https://lucenenet.apache.org home page.

### Exceptions (if any)

_No response_

### Lucene.NET Version

_No response_

### .NET Version

_No response_

### Operating System

_No response_

### Anything else?

_No response_

Start with the Apache Whimsy project checklist linked in the issue, then inspect the lucenenet.apache.org homepage and its website source. Check the Popular Books images and other listed requirements, keeping external resources on Apache servers; done means the homepage images work or the section is corrected and the listed requirements are addressed.

Written by the indexing model from the issue text.