Airlock base test file

[clemlak]

Description

Create a new base file for our testing suite that will put the Airlock contract at its core, instead of our current BaseTest file, which is oriented towards the Doppler contract.

Motivation

We reached a state where we're having several module contracts that are using and reusing different setUp function to initialize an environment with the Airlock contract. This is not convenient and having a base file will save us some time.

Proposed Solution

• Create a new Airlock base file for our tests, that will deploy the Airlock contract
• If possible, add a simple way to also deploy some modules