Add some demos #13
Description
The hal-http-client is very hard to describe without giving thorough examples. Nevertheless examples that cannot easily be run by anyone are not of much use and may degenerate after a while.
Hence the idea arose to add a sub folder with some examples (from simple to advanced), featuring a small nodejs server simulating a backend, and simple frontend applications showing the use cases with some additional explanations. This might then even be a source for code snippets to use in real projects.