Stibbons Testnet Reset

This Thursday 29 Jan 2021 will be the start of the Stibbons test net.
Ridcully will be retired shortly afterwards. The main reason for the reset is
the addition of kernel and output counts to the block headers to enable
better synching with a pruning horizon.
The coinbase lock height will increase to 60
The default confirmation time in wallets will be 6 blocks
The pruning horizon will be 1000 blocks and will be enabled by default. Full
archival nodes can still be run, by removing the pruning horizon setting from