chore(core): deprecate prefixed accessors/mutators in CommandManager.java
All prefixed (actual) getters/setters in CommandManager have been deprecated, and non-prefixed alternatives have been introduced. I've also put some effort into improving the JavaDocs of these methods.
adds a system for processing strings found in annotations before they're used by AnnotationParser
implements #347
Also, because we're using "-Werror", the code won't actually build (and thus tests won't work) using JDK18. To remedy this, a bunch of @SuppressWarnings("serial")s has been added to the exceptions. We don't serialize exceptions, and they're in fact non-serializable because of their members, so this is the appropriate solution (well, the better solution would be to make them serializable, but that's outside the scope of this PR).
* build: switch to spotless
add in some other basic formatting steps that allow for easy
auto-correction
* build: lint text files as well
* chore: remove license headers from package-info files
spotless can't verify these
