[chore] More low-hanging Sonar fruit

[timyates]

This commit:

• Use SLF4J formatting for log messages
  Instead of using String.format or String addition in LOG.info/warn/etc calls
• Remove unused injection points and imports
  We were injecting beans which we never used
• More unused imports
• Replace filter().findFirst().isPresent() with anyMatch() or noneMatch()
  This is just easier to read
• Use toList instead of Collectors.asList
  New for Java 16 (slightly different semantics, but I think we're ok here)