Add chicken or the egg dilemma: Reading deps_cpp_info

[uilianries]

Hi!

Eventually some users ask if is it possible to read self.deps_cpp_info when running configure or config_options. As we know, the dependencies graph is not ready yet.

We could include this problem under FAQ or Troubleshooting, using a common example, trying to list some option from a dependency and explaining about the dependencies graph. Actually, Memsharded made a great explanation in some issue, you could copy from there.

Related issues: conan-io/conan#4407 conan-io/conan#2218 conan-io/conan#4450 conan-io/conan#4401

Regards!