include a fake application in sample images

[flozanorht]

The two example images, which run either an Apache Web Server or a MySQL database server, just install the packages and enable the services. This is too distant from real-world examples.

It is planned to review those samples to use examples from other RHDE courses, and embed real applications, but maybe we can use file customizations and first boot services to include something that makes those images look less generic, such as including a custom welcome page or a sample database with hardcoded data.