* Move `checkstyle-conventions.gradle` content to the `build.gradle` since it is short enough
* Remove `checkstyle-header.txt` and its handling in favor of Spring Javaformat out-of-the box logic
* Upgrade to Gradle `8.5`
* Remove suppression for `Javadoc*` checks since it is handled by Spring Javaformat
* Leave only `MissingJavadocMethodCheck` exclusion from `SpringChecks` since all others really make sense for our code quality