Change integration tests to use Mocks

[kwek20]

Currently our integration tests are very fragile since they run on a live network.

Tests are susceptible to running to fast -> no confirmed balance
or someone spends the balance on a test seed, causing the test to break.

All tests should be running on an offline connection using Mockito mocks.

[chrisdukakis]

I'm actually considering to rewrite account tests as e2e. I think we could pass random seeds as encrypted env vars.

[kwek20]

Yea that would work, but i still think I need some integration tests before running regression, which mocks would do