Refactor Serialization

[elBoberido]

Brief feature description

The current cxx::Serialization massively uses std::string. This shall be solved by a refactoring.

Detailed information

To get rid of std::string in our code base, the cxx::Serialization needs to be refactored. Additionally, it should be possible to serialize into a binary format to speed things up and potentially reduce the serialized data size.

This will partly solve #260

Tasks:

• create design document
• implement cxx::SerDe
• replace cxx::Serialization with cxx::Serde

[elBoberido]

@Dennis40816 this is the corresponding issue for the serialization refactoring.

Some years ago I created a small proof of concept. You can find the commit here -> elBoberido@839a934

I'm a bit busy today but you can have a look at that code and try to understand what was in my mind :)