Donation match sender

[SovereignAndrey]

Closes: #22

Explanation of the solution

Variable created for holding the donation match, for use in Donation Matching flow. If passed in DepositRequest struct, under new donationMatch field, we use that address, otherwise we use the msg.sender for any messages that pass an address(0).

New AccountMessages.DepositRequest struct

struct DepositRequest {
    uint32 id;
    uint256 lockedPercentage;
    uint256 liquidPercentage;
    address donationMatch;
}

Instructions on making this work

• run yarn or yarn install to install npm dependencies
• run yarn test to verify all tests still pass