List all properties in the CppInfo section

Based on feedback from @jcar87 I also think it would be useful to list all of the existing properties in one place, probably the [CppInfo section](https://docs.conan.io/en/latest/reference/conanfile/attributes.html#cpp-info-attributes-reference).
Right now you can only check which properties are available in the reference for [each generator](https://docs.conan.io/en/latest/reference/conanfile/tools.html).