Introduction Integration Tests
This introduces these integration tests for the introduction client:
- normal session where both introducees accept
- normal session where the first introducee declines
- normal session where the second introducee declines
- one session where a contact is introduced to herself
- one session where two identities of the same contact are introduced to each other
I managed to get rid of the non-determinism missing validator problem by properly injecting the eager singletons.
Attention: This is based on !143 (merged) which addresses a corner case that is already tested here.