Add CI workflow for testing documentation examples

[kboyarinov]

Description

Add testing of code snippets from reference and user guide:

• Introduce CMake for examples testing
• Extract examples from rfc to external .cpp files
• Add CI workflow for testing on Linux

Userguide examples were not completely moved to .cpp from .rst yet
Testing on Windows was not enabled yet

Fixes # - issue number(s) if exists

Type of change

Choose one or multiple, leave empty if none of the other choices apply

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• bug fix - change that fixes an issue
• new feature - change that adds functionality
• tests - change in tests
• infrastructure - change in infrastructure and CI
• documentation - documentation update

Tests

• added - required for new features and some bug fixes
• not needed

Documentation

• updated in # - add PR number
• needs to be updated
• not needed

Breaks backward compatibility

• Yes
• No
• Unknown

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Other information

[aleksei-fedotov]

Finally, we are going to have this step automated! Hooray!

[isaevil]

Github Actions and CMake side looks good to me.