Provide the `usage` file of a package in the website

Currently, it is hard to know how we can use a package in CMake. Sometimes the CLI prints some information after it installs the package

```cmake
    find_package(fmt CONFIG REQUIRED)
    target_link_libraries(main PRIVATE fmt::fmt)
```
But this information is not available before writing the correct CMake file. It would be nice to have these CMake targets on the website.