Create integration tests for tuono_lib crate

[Valerioageno]

As the project is growing, we need to enforce reliability of the server we ship with tuono.
As the first step, we need to implement a reusable set of tools for testing the tuono_lib server crate within the tests/ folder.

[mustafasegf]

i wonder what kind of e2e testing are you thinking? i probably can do this but I need more context on how to approach it

[Valerioageno]

I don't have any strong opinion yet...
The idea would be to test that a server built using the tuono_lib structs/functions/macros correctly return the right responses.

I'm wondering what would be the best place in which to put it.
The only idea I got so far is to create a bin crate in which create a fake server using just tuono_lib with a bunch of handlers and then leverage the tests/ folder integration tests.

WDYT? I'm open to other ideas as well!