Change Oracle Period for SP2 from 4 Hours to Less

Change the Oracle time period window (which calculates the D-bill purchase period for a reward cycle) from 4 hours to a lesser time (30 minutes, 1 hour, 1.5 hours, 2 hours) period.

Reason: a smaller time window will reduce the number of D-bill purchases per reward cycle, increasing the DEBASE rewards to those who enter the pool.

This will create a positive feedback loop: less D-bills purchased (due to lower time frame for purchases) > more rewards per Sp2 Reward cycle > more speculators buying D-bills when SP2 pool opens > increased activity of SP2 pool > more stability for Debase