Paper plugin migration

[NonSwag]

Description

This PR makes the plugin a paper plugin.

• made necessary changes to "goPaint plugin check"
• removed unnecessary java/game version checks
• renamed Handler to GoPaintCommand

Checklist

• I included all information required in the sections above
• I tested my changes and approved their functionality
• I ensured my changes do not break other parts of the code

[sonarqubecloud]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud