Add Support for Display of ExternalReference Hashes

[msymons]

Current Behavior

Dependency Track UI displays External References for project/component/service via a tab on the "View Details" dialog.

The dialog in v4.10.1 displays "URL" and "Type" and support for "Comment" was added via issue #802 and will be in v4.11

The only element of External References that are NOT yet displayed are hashes.

Proposed Behavior

When hashes exist for an ExternalReference then they should be displayed in the Frontend. Hashes are an array containing algorithm (alg) and content, so the display should be capable of handling multiple hashes for a single External Reference, and also identifying what algs are used.

See relevant specification documentation here and here

This enhancement is specific to "display-only" and is thus an MVP. Future functionality might include (optionally) checking the hashes (eg using integrity checking to be implemented in DT v5.0 (Hyades)).

Checklist

• [X] I have read and understand the contributing guidelines
• [X] I have checked the existing issues for whether this enhancement was already requested