build: split up into multiple projects, use kotlin DLS

buildSrc/build.gradle.kts

@@ -0,0 +1,7 @@
+repositories {
+	mavenCentral();
+}
+
+plugins {
+    `kotlin-dsl`
+}

buildSrc/src/main/kotlin/common-java.gradle.kts

@@ -0,0 +1,12 @@
+plugins {
+	id("common");
+}
+
+java {
+	sourceCompatibility = JavaVersion.VERSION_17;
+	targetCompatibility = JavaVersion.VERSION_17;
+
+	toolchain {
+		languageVersion = JavaLanguageVersion.of(17);
+	}
+}

buildSrc/src/main/kotlin/common.gradle.kts

@@ -0,0 +1,11 @@
+plugins {
+	id("java");
+}
+
+version = rootProject.version;
+group = "${rootProject.group}.${project.name}";
+base.archivesName = "${properties["project_name"]}-${project.name}";
+
+tasks.named<JavaCompile>("compileJava") {
+	options.release.set(8);
+}