scripts: west_commands: zspdx: add default values from zehpyr meta from purl and version

[SchlegNi]

With this PR west spdx will include the information about the modules from zephyr.meta into the SBOM as default values, and override this values if a module has defined a security entry in its module.yml file.
With this change, the modules-deps.spdx would represent which versions are actually used. And tools like dependency-track are able to track used packages by the purl entry.

[github-actions]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud