Include link to view finding in API response

### Current Behavior

`/v1/finding/project/{uuid}` returns an object that doesn't include a URL to view the finding in the UI.

### Proposed Behavior

Include a `web-url` field (or similar - I don't think there's precedent for this field name yet?) alongside the matrix that links to the frontend: `http://{frontend}/projects/{project uuid}/findings/{component uuid}/{vuln uuid}`.

It is already possible to build this URL from the matrix, but it's not obvious that this route exists - it isn't exposed in the UI in any way, so presenting it in the API response makes it much more usable.

This depends on [frontend/#689](https://github.com/DependencyTrack/frontend/pull/689) being merged for this URL to work.

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The generic version of this enhancement is adding links to all of the relevant API responses: components, projects, vulnerabilities, policies, violations, etc. This specific one is the most impactful, as it's not easily discoverable via the frontend.

### Checklist

- [X] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/master/CONTRIBUTING.md#filing-issues)
- [X] I have checked the [existing issues](https://github.com/DependencyTrack/dependency-track/issues) for whether this enhancement was already requested