Make L2 rich accounts properly deposit their funds from L1

[jrchatruc]

Currently the L2 has rich accounts that are directly given funds on the genesis block. We should instead make rich accounts from L1 deposit their funds into the L2 on network initialization (i.e. after make init finished and the L2 first starts) and remove them from the genesis file. This way we actually have all L2 funds be in 1-to-1 correspondence with the L1 contract funds.