Remove tests that only worked with exoscale v2

In exoscale v2 we had an interface for the exoscale client, which
allowed us to use mockery to create mocks for the tests.
Unfortunately v3 doesn't use any interfaces anymore, which makes moking
a client much more complicated.
We therefore remove those tests for now

Signed-off-by: Nicolas Bigler <nicolas.bigler@vshn.ch>

Author: TheBigLee