Make WireMockServer start/stop/shutdown fluent

[gliptak]

References

#3052

Submitter checklist

• [ ] Recommended: Join WireMock Slack to get any help in #help-contributing or a project-specific channel like #wiremock-java
• [x] The PR request is well described and justified, including the body and the references
• [x] The PR title represents the desired changelog entry
• [x] The repository's code style is followed (see the contributing guide)
• [x] Test coverage that demonstrates that the change works as expected
• [ ] For new features, there's necessary documentation in this pull request or in a subsequent PR to wiremock.org

[gliptak]

@tomakehurst please approve workflow runs

[gliptak]

@leeturner @Mahoney please approve workflow runs

[RafeArnold]

thanks!

[RafeArnold]

documented breaking changes here