Refactor web server

[kuznetsss]

It would be nice to hide all the implementation of the web server into a library and make usage simple. Usage should be like:

Server server(ip, port);
server.onGet("/", getCallback);
serveer.onPost("/", postCallback);
server.run();

[kuznetsss]

This is needed for #442 so moving it to the 2.3 milestone.