[5] TWAP strategy should hit the bid when in submit mode "both"

[nikhilsaraf]

• Add a configuration in number of seconds X which dictates how many seconds into the bucket we should attempt to hit the bid
• the price we use should be a default 1% below the best bid (needs a new price feed).
• additional test for the pricing component (Round struct)
• this enables the twap strategy to achieve better execution