Add support for system_libs and frameworks for Qbs generator

[Psy-Kai]

Changelog: Feature: Added support for cpp_info.system_libs, cpp_info.framework_paths and cpp_info.frameworks for qbs generator.
Docs: Omit

partially implements #6008

• 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.}

[CLAassistant]

All committers have signed the CLA.

[memsharded]

Looks good, many thanks.
We don't have specific unit test for this generator, I guess you managed to run it locally from sources with the changes, and it is working for you, isn't it?

[Psy-Kai]

Looks good, many thanks.
We don't have specific unit test for this generator, I guess you managed to run it locally from sources with the changes, and it is working for you, isn't it?

Yes. I modified my running conan instance and used the Qbs generator before uploading the code.