Update files to match checkstyle (part 1)

[Efnilite]

Description

Updates some of the worst offenders, who are least likely to be affected by other PRs.

• Removed the copyright header, used IntellIJ's formatting shortcut, and split lines that were >120 chars.
• Moved the Parsers and Serializers in JavaClasses to separate inner classes with IntellIJ's "To named inner class" shortcut.
• Renamed variables and removed finals

Removes around 700 violations, or 10% of total.

---

Target Minecraft Versions: any Requirements: none Related Issues: none