The package_type deserves a better documentation

The Conan 2.x attribute `package_type` is minimally documented in [Docs: package_type attribute](https://docs.conan.io/2/reference/conanfile/attributes.html#package-type), and is referred in others parts, but not explaining about its scenarios.

Meanwhile, its [design](https://github.com/conan-io/tribe/blob/main/design/027-package_types.md#detailed-design) is much more useful, giving examples of real scenarios.

It would be better including some examples in the docs, that are frequently asked in CCI:

- What should be the package type when having both executable and libraries in a package?
- Should change the package type when having header-only as option?
- Should change the package type when having option to package only executables?