Embed documentation in API Spec

[monamok]

What type of PR is this?

• documentation

What this PR does / why we need it:

Update API documentation according to v0.3.0 API version definition. The documentation will be added to the API definition as discussed in camaraproject/WorkingGroups#164. It was agreed that the CAMARA documentation should be embedded in the OAS definition and not separate. This will reduce the effort to maintain the documentation.

This PR is aligned to QualityOnDemand PR camaraproject/QualityOnDemand#151

Which issue(s) this PR fixes:

Fixes #37

Special notes for reviewers:

• Multi-line descriptions formatted as |
• UML diagram added in order to clarify the end-to-end flow
• External resources such as images and other docs are linked to the absolute paths in Github: ![Alt text](https://full_path?raw=true)
• As for linking images the absolute paths are required and the UML file still doesn't exist in CAMARA repository for the moment the link from my repository is being used. Once the PR is merged, another PR must be opend to change the UML URL that is created in the main branch.

Visualizations tested with editor.swagger.io

[DT-DawidWroblewski]

auth call very high level, but overall sequence is good