Create docker image for TRSS for new users

For new users, it will much easier if we have a TRSS docker image for them to try. Sample data should be inserted into database, so users can see the graphs or pipelines.

This docker image can also be used for setup PR build https://github.com/AdoptOpenJDK/openjdk-test-tools/issues/374

Start by reviewing the TRSS setup and the linked issue #374 to understand how a Docker image would support new-user trials and PR builds. Define the image's sample database data and verify that users can view graphs and pipelines and that the image works for the PR build setup.

Written by the indexing model from the issue text.