Improvement: Add building of documentation to CICD

[MaximilianSoerenPollak]

Currently in this repo we are not building the Documentation as part of CI/CD tests.

This should be integrated.

Which documentation should be build?

• Only build one example?
• Build all examples?
• Have a seperate 'doc', where we might publish documentation instead of examples, and build that?

[MaximilianSoerenPollak]

Current proposal.

docs

• extension documentation
• docs-as-code 'how to'
• FaQ
• example
  • rendered example

[MaximilianSoerenPollak]

Done. Integrated with: #55