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

app/build.gradle.kts

@@ -6,9 +6,6 @@ plugins {
     application
 }
 
-group = "org.nixos"
-version = "1.0.0-SNAPSHOT"
-
 dependencies {
     implementation(project(":model"))
     implementation(kotlin("stdlib-jdk8"))