New docs/tutorials

[hansb001]

Proposed changes

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[didier-wenzek]

I will take the time for a review on Monday.

Beware that the last 2 commits are strange and need to be removed. I will help you to remove them.

[didier-wenzek]

• Since the plan is to finalize the child-device.md doc in a follow-up PR, it's better to remove a draft from this one.
• It would be better to avoid long lines that make diff a bit difficult to read. This also confuses the gui and some suggestions are blocked.

[didier-wenzek]

Approved.