Use custom dependency resolution

- Use Apache Ivy to resolve artifact URLs
- Update build model with full artifact IDs
- Generate Maven module metadata to support dynamic version constraints
- Resolve snapshot versions and generate snapshot metadata
- Add test fixtures and rewrite Gradle plugin tests
- Update dependencies

fixtures/subprojects/multi-module/kotlin/build.gradle.kts

@@ -0,0 +1,13 @@
+plugins {
+    java
+}
+
+allprojects {
+    repositories {
+        jcenter()
+    }
+}
+
+dependencies {
+    testImplementation("junit:junit:4.12")
+}