Add integration test for the embed-code

[dmytro-kashcheiev]

Add a small project to verify how embed-code behaves in general.

Proposed solution:
Create documentation for embed-code that describes the purpose of the embed-code methods using explicit code examples from the embed-code repository.

• Insert code from the root of the repository.
• Then insert code from several different sources.
• etc.

TBD. This could be a separate repository, or it could live in the current repository alongside the code.
Other ideas are welcome.