Add Fetchcode support for BItnami

- No Standard Download Endpoint
Bitnami does not expose a standardized or public API endpoint that maps a PURL (like pkg:bitnami/wordpress?distro=debian-12) to a downloadable artifact URL

- Dynamic and UI-Driven Distribution
Bitnami primarily delivers packages via dynamic download pages (e.g., https://bitnami.com/stack/wordpress/installer) rather than static URLs or repository-like indexes. Files are often served behind redirect chains that involve JS or token validation.

- Lack of Versioned Index or Manifest
There is no accessible versioned package index (like Packages.gz or repodata/primary.xml) to crawl or query for mapping names to URLs. This makes automation infeasible without scraping or reverse-engineering the frontend.

- Cloud-Native and VM-Image Focus
Bitnami PURLs often refer to entire stacks or VM/container images, not raw binaries or .deb/.rpm packages. The “download” could refer to an OVA, Docker image, or even a marketplace listing—none of which follow a conventional artifact URL format.

- No Universal Host for Artifacts
Bitnami-hosted downloads may come from AWS S3, Akamai, or Azure depending on the region and platform, with presigned URLs that expire. These cannot be deterministically generated or reused.