Replace usages of `FileResolver.resolveFile()` with `FileCollectionFactory.resolving()` or `FileOperations.immutable()`, so that `FileResolver` can be responsible only for converting scalar values to File-ish values.
Remove special repository default behavior with GRADLE_METADATA flag The default behavior is now that we look for 'traditional' metadata first, but find Gradle metadata if a marker is present. We won't look for anything else if the 'traditional' metadata is not found. This increases performance for the cases where one repository is asked for many modules it does not contain. Users can opt into different behavior using `gradleMetadata()` or `artifact()` when defining their repositories.