Add option to download archive with all outputs/results

[tsteenbe]

It's not unusual for license compliance or OSPO professional to trigger multiple scans and afterwards download all result files so they can be reviewed locally. Currently in ScanCode v35.3.0 and earlier one can only download results one file at a time - it would be much more convenient for users if there was a

1. Download icon within the "Outputs" header on the right which once hovered over shows "Download all outputs" button and once clicked would download a zip archive including outputs.
2. "Download all results" button which once clicked would download a zip archive including all result formats (JSON, XSLX, SPDX, CycloneDX, Attribution, Tools formats)

[mjherzog]

A current workaround is to script this from the command line.

[tdruez]

PR #1910 introduces the following:

• Ability to download all output results formats: New "All formats" option is available from the project list "download" dropdown and from the project detail view "downloads" section. It returns a zip file containing all supported output formats.
• Ability to download all existing outputs for a project. Any output file generated during or after a pipeline run will be included in the zip file. A new "Download all outputs" button is available at the bottom of the "Outputs" pannel in the project detail view.
• The all_formats and all_outputs are available in the REST API for the "results_download" action.
  GET /api/projects/{uuid}/results_download/?output_format=all_formats

---

In addition to those new features, the ability to download outputs for multiple selected projects is already available through the project list "Actions" > "Download" feature.