feat: support fetching Maven dependencies from artifact registry

[cuixq]

This PR introduces support for using Artifact Registry as a remote Maven repository. Users can now fetch Maven dependencies from artifact registry with a URL with the artifactregistry:// scheme.

When we see a new Maven registry, if it's artifact registry, we try to create google.DefaultClient so requests can be authenticated. This automatically handles authentication using Application Default Credentials (ADC).

After the client is created, when we try to make a request, if it's for artifact registry, we use this client; if the client is not available, we fall back to the default HTTP client. We also log StatusForbidden error for artifact registry.

References:

• https://github.com/GoogleCloudPlatform/artifact-registry-maven-tools/tree/master/artifactregistry-maven-wagon
• https://github.com/GoogleCloudPlatform/artifact-registry-go-tools/blob/main/pkg/auth/auth.go

[michaelkedar]

LGTM