Closes #15

• Liquidates loans that the bot's balance can repay (no DEX swaps)
• Attempts to redeem the qToken liquidations reward so the underlying can be used for future liquidations
• Uses a greedy strategy to find the most profitable liquidation (the most valuable collateral currency of the borrower with the largest debt, considering what the bot can repay and the close factor of that market)
• On each block, queries the chain to compute undercollateralizations
• (You can ignore this one) Upgrades the bridge-tester to a more recent lib version - was checking to see if yarn build and yarn test are successful across all workspaces