Implement Public Allocator

[adhusson]

Summary

tldr
Main function is reallocateTo(Withdrawal[] calldata withdrawals, MarketParams calldata supplyMarketParams), it is callable by anyone. withdrawals is a list of (market,amount) pairs. The function will try to withdraw the given amount from each market and then deposit the total withdrawn to depositMarketParams, subject to admin-settable constraints.

Max flows
Each market has a max inflow (maxIn) and a max outflow (maxOut). For every call to reallocateTo:

• The markets in withdrawals increase their maxIn and decrease their maxOut by the amount withdrawn.
• The market depositMarketParams increases its maxOut and decreases its maxIn by the total withdrawn.

The owner can configure the max inflows/outflows.

Supply caps
Each market has a supply cap that works like MetaMorpho's supply caps. The owner can configure the caps.

Fee
The PublicAllocator has a fee (payable in ETH). The owner can configure the fee. The owner must call transferFee to take the accumulated fees out of the PublicAllocator.

Checks
The PublicAllocator will make the following checks when reallocateTo is called:

• No market's maxIn or maxOut is exceeded.
• No market's supply cap is exceeded.
• The fee has been paid.