[Spike] Try out Spotless; outcome: Do include Spotless in the project

[jwlibby]

Try out Spotless and see what you think. When evaluating refer to the questions in #462 and upon completion add your pros and cons for this plugin as a comment to the aforementioned story. Plugin link: Spotless.

Considerations for implementation cards:

• Gradle: easy
• Maven: lots of challenges, dependencies: Plexus, SLF4J, Kotlin, Eclipse; the plugin dependency wants Sonatype rather than Maven Central also easy. The challenges and dependencies issues mentioned were because I had incorrectly added the plugin as a dependency, not as a plugin

Related: #534 for epic on dependency management.