feat: Tests initial structure | NPG-000

[kukkok3]

Proposing new integration tests structure ispired by rust-lang/cargo#4867
Example:

tests/
       component/
             main.rs
             component1.rs
             component2.rs
      integration/
              main.rs
              component1_component2.rs
      end2end/
             main.rs
             voting.rs       
      non_functional/
                main.rs
                load.rs

In this way we will have 4 crates. Performances could be improved by having only one crate but I think the structure will became to messy
Ideas welcome @nicopado @stevenj

[nicopado]

LGTM

[stevenj]

LGTM