dev: switch to stonecutter build system

- This will allow us to build the library for different Minecraft versions at the same time
- Right now, only Fabric and Neoforge 1.21.10 are fully working
- As a bonus, the jar is now even smaller!

buildSrc/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+    `kotlin-dsl`
+    kotlin("jvm") version "2.0.20"
+}
+
+repositories {
+    mavenCentral()
+}

buildSrc/src/main/kotlin/build-extensions.kt

@@ -0,0 +1,33 @@
+import org.gradle.api.Project
+import org.gradle.api.artifacts.dsl.RepositoryHandler
+import org.gradle.kotlin.dsl.expand
+import org.gradle.kotlin.dsl.maven
+import org.gradle.language.jvm.tasks.ProcessResources
+import java.util.*
+
+val Project.mod: ModData get() = ModData(this)
+fun Project.prop(key: String): String? = findProperty(key)?.toString()
+fun String.upperCaseFirst() = replaceFirstChar { if (it.isLowerCase()) it.uppercaseChar() else it }
+
+fun RepositoryHandler.strictMaven(url: String, alias: String, vararg groups: String) = exclusiveContent {
+    forRepository { maven(url) { name = alias } }
+    filter { groups.forEach(::includeGroup) }
+}
+
+fun ProcessResources.properties(files: Iterable<String>, vararg properties: Pair<String, Any>) {
+    for ((name, value) in properties) inputs.property(name, value)
+    filesMatching(files) {
+        expand(properties.toMap())
+    }
+}
+
+@JvmInline
+value class ModData(private val project: Project) {
+    val id: String get() = requireNotNull(project.prop("mod.id")) { "Missing 'mod.id'" }
+    val name: String get() = requireNotNull(project.prop("mod.name")) { "Missing 'mod.name'" }
+    val version: String get() = requireNotNull(project.prop("mod.version")) { "Missing 'mod.version'" }
+    val group: String get() = requireNotNull(project.prop("mod.group")) { "Missing 'mod.group'" }
+
+    fun prop(key: String) = requireNotNull(project.prop("mod.$key")) { "Missing 'mod.$key'" }
+    fun dep(key: String) = requireNotNull(project.prop("deps.$key")) { "Missing 'deps.$key'" }
+}