rewrite docker tutorial

[Mateusz512]

Motivation and Context

Docker tutorial involved too many concepts. Now it's just a matter of creating new Handler

Types of changes

Simplify the tutorial. Use new starter-kit (capable of docker/stack build)

Checklist:

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [not yet] I have updated the documentation accordingly.

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I hereby agree to the terms of the Knot.x Contributor License Agreement.

[tomaszmichalak]

azure-pipelines.yml

after stack build please add:

- script: |
    ./distribution/docker/gradlew -p ./distribution/docker build-docker --info
  displayName: 'Build: Distribution -> Docker'