Catch exception state on ilink web service #212

[Tiago-da-silva23]

This PR includes the ilink exception handling, resolve #212.

[igobranco]

You need to include a 404 test.
A test that mocks the iLink 404 document not found.
And test/check if the client is returning a 404 when the upstream getDocument returns a 404.

[igobranco]

I've added a commit to the branch that merge the mock function with its test.

It isn't a good practice to have a different function that is too tight with its test outside of test. So I've replaced it with a lambda.

I would like other solution, but this is more practical.

LGTM ✅