Add repeating checks for high fees required due to long contract queue

[TobiWo]

Summary

The queue of open consolidation or exit requests influences the fee which need to be send as value along a respective transaction exponentially. Therefore a respective log is needed if the queue is long, hence resulting in high fees.

Details

1. Add trx cost threshold to be provided by user

• Cost threshold is tested against calculated contract fee -> for each batch/block
• Warning is logged with trx costs in eth and execution is halted
• User is asked to continue or abort

2. Add a fee only mode (via separate --fetch-fees flag) which simply logs system contract fees for each block -> as convenience so that the user keeps track of the state of costs
3. Predict/Caluclate trx costs while taking number of trx which will be send into account