build: install cmakes find package files

[gocarlos]

what

• installs cmake files when make install
• add cmake usage to readme
• make sure CI also runs on pull requests for fork workflow

  why

• allows people to use cmake built in find_package

[arun11299]

@gocarlos Thanks for the pull request. But I see that the checks are failing. Is it causing builds to fail ?

[gocarlos]

conan pipeline is failing due to bug: https://github.com/conan-io/conan-center-index/issues/952

this conan bug should though be fixed with conan 1.26 with was released recently