Review "Creating Your Own Starter"

[snicoll]

Based on a question from @ohubaut at the BruJUG, I think we probably need to review the Creating Your Own Starter section. Following the modularization, we're more leaning towards spring-boot-<tech> and spring-boot-starter-<tech> rather than using the autoconfigure term.

We could recommend acme-spring-boot and acme-spring-boot-starter? Some notes on importing only the modules that you need could be also helpful to guide users as well as the separation between a module and a starter, the latter adding a more opinionated set of dependencies than the former.