v4.0.0

• IMPORTANT: Changed the name of the library from CPP-AP to CPP-ARGON
• Aligned the CMake and Bazel build targets to use the new library name
• Changed the library namespace from ap:: to argon::
• Aligned the name and content of the cpp-ap-demo submodule repository to use the new library name
• Added a new project logo and aligned documentation postprocessing to display it properly