Provide some global mocks

[ivolimasilva]

When using @testing-library, we can only render the full tree and therefore the child components are rendered too. These child components may use some libraries or functions that are not available in the jsdom version that Jest uses, generating errors for the component we actually want to test.

When testing a component, we shouldn't have to worry about what dependencies its child has so there should be a global generic mock available.