Add Depends item for every public_dep of the conanfiles deps

[Psy-Kai]

Changelog: Feature: Added Depends items for every public dependency of conanfiles requires/dependencies.
Docs: conan-io/docs#1847

Fixes #7728.

The usage of publilc_deps is based on the implementation of the pkg_config generator.

• Refer to the issue that supports this Pull Request.
• If the issue has missing info, explain the purpose/use case/pain/need that covers this Pull Request.
• I've read the Contributing guide.
• I've followed the PEP8 style guides for Python code.
• I've opened another PR in the Conan docs repo to the develop branch, documenting this one.

^{Note: By default this PR will skip the slower tests and will use a limited set of python versions. Check here how to increase the testing level by writing some tags in the current PR body text.}

[memsharded]

Thanks for this contribution!
I have added a unit test, to make sure this doesn't break in the future.
Lets merge it for next Conan 1.30 release.