Support building with java 21

[ctubbsii]

• Require Java 21 for build (does not change runtime requirements)
• Update GitHub Actions workflows
• Update ASF Parent POM to latest and update some plugins
• Fix some issues caught by the new compiler and/or spotbugs
• Suppress 'this-escape' category of compiler checks, because of too
  many false-positive issues, including with generated thrift code that
  is hard to suppress on a case-by-case basis
• Add dependency exclusion analysis (checks for unnecessary exclusions)
• Update errorprone to work with Java 21

[ctubbsii]

I ran mvn clean verify javadoc:jar -Psunny with these changes, and everything passed fine. If we want to still allow building with Java 17, we'd have to avoid upgrading checkstyle, and move the -Xlint:-this-escape argument to a profile, which makes things more complicated.