GPT: Add Tech Docs (a documentation template)

[christophe-f]

The template will ask which component to link with and create a new repo.

EntityPicker:
        type: string
        ui:field: EntityPicker
        ui:options:
          catalogFilter:
            - kind: component

For example a component with the name node-website will have a new repo node-website-techdocs

The template skeleton will contain the mkdocs.yaml with the /docs folder contains a sample index.md
It will also create the GitHub Action pipeline. For example the one from Showcase: https://github.com/janus-idp/backstage-showcase/blob/main/.github/workflows/techdocs.yaml

No need to do Tekton pipeline yet.

Issues in Epic

• Documentation need for GPT: Add Tech Docs (a documentation template) #154 [Doc]
• Testing needs for GPT: Add Tech Docs (a documentation template) #155 [QE]

[jasperchui]

Reopen and convert to EPIC and capture doc and testing requirements.