Replace Alcotest unit tests with Jane Street's Inline Tests

[johnyob]

Dromedary's current testing framework relies on Alcotest, QCheck and Jane Street's Expect Tests.
This issue aims to remove Alcotest by using Jane Street's Inline Tests:

let%test_unit "single" = 
  assert (...)

let%test_unit "many" = 
  for i = 0 to 100_000 do
    ...;
    assert (...)
  done