Improve gradle

[makeevrserg]

Summary

Migrate Gradle build scripts to Kotlin DSL with a version catalog.

Changes

No functional changes. Build outputs are identical

1. .gradle converted into .gradle.kts (except /plugin/build.gradle)

• IDE now provides auto-completion, click-to-navigate, and compile-time error checking for build scripts.
• Groovy scripts are dynamically typed. A typo compiles fine and crashes at a runtime

2. Added version catalog libs.versions.toml

• All dependency versions in one file
• libs.minecraft.velocity.api instead of "com.velocitypowered:velocity-api:$velocityVersion"
• Typo in the old way == silent empty string
• Typo in the new way == compile error

3. Type-safe project accessors

• projects.api instead of project(":api")
• Rename a module and the build fails immediately, not at runtime

[UserNugget]

No longer builds, see this

[makeevrserg]

Something went wrong after rebase on newly merged PRs, fixed it