feat: add scaffolder action for the scaffolder relation link

[Zaperex]

Description

Adds a custom scaffolder action appends the spec.scaffoldedFrom field to the catalog-info.yaml of the generated catalog entities. Used in conjunction with the scaffolder relation processor to form relation links between scaffolder templates and the entities they generate.

What issue(s) does this fix?

Fixes: RHIDP-2221

How to test changes / Special notes to the reviewer

1. Install the module using the instructions in the README.md
2. Import a template with the scaffolder action. ex:

catalog:
  locations:
    - type: url
      target: https://github.com/Zaperex/backstage-plugins/blob/76062120bd68f78d658f7b4c781611c2c3c95b42/plugins/scaffolder-backend-module-scaffolder-relation/examples/01-scaffolder-relation.yaml
      rules:
        - allow: [Template]

3. Use the template to register a catalog entity into the catalog and observe that the spec.scaffoldedFrom field exists and its value matches the entityRef of the template that generated it.
4. If the scaffolder relation processor, the dependency graph of the ingested component should include a scaffoldedFrom link to the template

[openshift-ci]

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[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[Zaperex]

Closing in favor of #1567