fix: standalone module builds work again

Standalone module builds lack the buildscript block from the engine workspace, we can add it here, but ... noisy.

In Jenkins we also attach the buildSrc dir now for module builds

Jenkinsfile

@@ -7,7 +7,7 @@ node ("default-java") {
     stage('Build') {
         // Jenkins sometimes doesn't run Gradle automatically in plain console mode, so make it explicit
         sh './gradlew --console=plain clean extractConfig extractNatives distForLauncher'
-        archiveArtifacts 'gradlew, gradle/wrapper/*, templates/build.gradle, config/**, facades/PC/build/distributions/Terasology.zip, build/resources/main/org/terasology/version/versionInfo.properties, natives/**'
+        archiveArtifacts 'gradlew, gradle/wrapper/*, templates/build.gradle, config/**, facades/PC/build/distributions/Terasology.zip, build/resources/main/org/terasology/version/versionInfo.properties, natives/**, buildSrc/src/**, buildSrc/*.kts'
     }
     stage('Publish') {
         if (env.BRANCH_NAME.equals("master") || env.BRANCH_NAME.equals("develop")) {

templates/build.gradle

@@ -1,5 +1,25 @@
 // Copyright 2020 The Terasology Foundation
 // SPDX-License-Identifier: Apache-2.0
+// Since SpotBugs and SonarQube in the legacy style have external dependencies we have to have this block here.
+// Alternatively we untangle and update the common.gradle / Kotlin Gradle plugin stuff or just remove these two
+buildscript {
+    repositories {
+        // External libs - jcenter is Bintray and is supposed to be a superset of Maven Central, but do both just in case
+        jcenter()
+        mavenCentral()
+        maven {
+            url = uri("https://plugins.gradle.org/m2/")
+        }
+    }
+
+    dependencies {
+        //Spotbugs
+        classpath("gradle.plugin.com.github.spotbugs.snom:spotbugs-gradle-plugin:4.0.0")
+
+        // SonarQube / Cloud scanning
+        classpath("org.sonarsource.scanner.gradle:sonarqube-gradle-plugin:2.8")
+    }
+}
 
 plugins {
     id("terasology-module")