Overview

This pull request targets to improve the kit contents (de)serialization.

##Changes:

• Specify table name for ClaimedKit
• Update items field to use byte array for kit content storage
• Remove unused (de)serialization methods and improve inventory handling
• FIx cooldown calculation on kit setup.

Submitter Checklist

• Make sure you are opening from a topic branch (/feature/fix/docs/ branch (right side)) and not your main branch.
• Ensure that the pull request title represents the desired changelog entry.
• New public fields and methods are annotated with @since TODO.
• I read and followed the contribution guidelines.