- Migrate tests to junit5 and assertj as those
are on a classpath automatically.
- Temporarily use spring.main.allow-circular-references=true
to allow time for fixes to remove cycles.
Just like spring-shell/spring-shell-samples shows examples of Spring
Shell features, create a project with samples of Spring Shell unit,
functional and integration tests.
Issue: SHL-192
https://jira.spring.io/browse/SHL-192