118: Add minimum monero confirmations to config use it for Bob r=da-kami a=da-kami
After discussion with @bonomat about enforced `10` confirmations until a tx is spendable on Monero I gave it a try with only `1` confirmation on regtest happy-path-test and `5` for `stagenet` and did not encounter problems. Both swaps passed without problems so I am proposing to merge these changes.
One additional change crept in: Changed the average blocktime for `stagenet` to `4` mins, because the blocktime fluctuates a lot. See: https://monero-stagenet.exan.tech/
Co-authored-by: Daniel Karzel <daniel@comit.network>