write some end to end tests to check that the behaviour is correct

[MarshallAsch]

In addition to the unit tests that will be developed as part of #25 making some tests to make sure that network level behaviour is correct will also be important. These tests should consist of fully fledged simulations that are small and will test components such as timeouts actually getting triggered, or not getting triggered, etc.

• lookup timeouts get triggered when set to a non 0 value
• lookup timeouts never happen when set to 0
• elections get triggered if a replica node is AWAL
• a node will step down if its battery gets too low
• a node will step down if it runs out of storage space
• other tests that I can not currently think of

[MarshallAsch]

odd edge case found:

• if the nodes are stationary / network connections are stable, then all nodes will become replica holder nodes.
• inital replica election, while t < T second, or if the check election result happens (when t==T) before the table gets updated all nodes will automatically become replica nodes.