Linux: conan 2 action-v1 & codecov action-v5

CI with Github Actions in Linux
Using Conan v2 with action v1
Coverage with lcov uploaded to codecov using action v1

First compiling version

This is the initial version that compiles the executable target and the all_tests target in the three main platforms: Windows (x32 VS 2019 - Debug), Linux (Ubuntu 20.04 - g++-10 - Debug), and Mac (OSX 10, apple-clang-12 - Debug/Release)