[CMake] Add main CMakeLists

Some reference here:
https://jrl-cmakemodules.readthedocs.io/en/master/pages/cmake-packages.html#minimal-working-example-with-cmake-packages

CMakeLists.txt

+cmake_minimum_required(VERSION 3.1)
+
+# Project properties
+set(PROJECT_NAMESPACE gepetto)
+set(PROJECT_NAME example-adder)
+set(PROJECT_DESCRIPTION "This is an example project, to show how to use Gepetto's tools")
+set(PROJECT_URL https://gitlab.laas.fr/${PROJECT_NAMESPACE}/${PROJECT_NAME})
+
+# Project configuration
+set(PROJECT_USE_CMAKE_EXPORT TRUE)
+
+# JRL-cmakemodule setup
+include(cmake/base.cmake)
+
+# Project definition
+COMPUTE_PROJECT_ARGS(PROJECT_ARGS LANGUAGES CXX)
+project(${PROJECT_NAME} ${PROJECT_ARGS})