Create new ads service in Java

[stanleegoodspeed]

Description

This PR adds a new service called ads-java. It is basically a duplicate of the existing ads service except it's written in Java. The purpose here is to create a Java service so the container can be used to display Java profiling or any other DD product with a Java integration.

How to test

1. Pull down this branch, run docker-compose up
2. Go to frontend repo
3. In env.local, switch the NEXT_PUBLIC_ADS_PORT to be 3030
4. Start frontend
5. Make sure ads continue to be served on the homepage

Before you move on, make sure that:

• No unintended changes are included
• Spelling is correct
• There are tests covering new/changed functionality
• Commits have meaningful names and changes. CR remarks-like commits are squashed.
• Proper labels assigned. Use WIP label to indicate that state

[devindford]

Works as expected, ads continue to load when port is changed to point at the java implementation