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/plugin/resolves-from-default-repo/groovy/build.gradle

@@ -0,0 +1,7 @@
+plugins {
+    id "org.jetbrains.kotlin.jvm" version "1.3.50"
+}
+
+repositories {
+    jcenter()
+}