Feed security module that delays upcoming price data from being pushed in the system

The Feed Security Module is a generalized, OSM-like framework where we experiment with different strategies to introduce a delay between a new price feed coming in a FSM contract and then being pushed in the core system.

For now we focus most of our development efforts on the OSM (that we inherited from the MCD codebase) but are also experimenting with DSM (Dampened Security Module).