Very basic example to show how a custom configuration can be associated to a Conan profile
using the conan.config.json file. In this example the custom profile modifies an
option of the fmt library, which in turn introduces a preprocessor definition that
is used in the main function to write additional output.
This example has a conanfile.txt with a dependency on the popular formatting library fmt. When the project is first opened, Visual Studio is unable to find the fmt project dependency. The extension should immediately run however, after it the fmt headers should be found by the compiler, and the lib files should be found by the linker successfully.