Add cutoff seconds to predictoor

[trizin]

Two sided predictions require a cut off seconds which will stop prediction submission when seconds left in the epoch is smaller than the cut off time. This is required to ensure that predictoor stakes on each side.

The minimum recommended cut off seconds is: 50 seconds. To have enough time for:

• 2 prediction txs
• 2 failsafe txs if something goes wrong with the predictions txs.

Todo:

• Implement s_cutoff under bot features in ppss.yaml, update predictoor_ss and add it as a property
• Stop all prediction submissions if seconds left in epoch < s_cutoff