Deprecating Batch Auctions in yield DTFs

ABC Labs will be proposing the deprecation of Batch Auctions across all yield DTFs.

A bug was found in a 3rd party contract used by Reserve yield DTFs. It was never exploited, the risk has been mitigated, and funds are safe.

More info here: https://medium.com/reserve-currency/deprecating-yield-dtf-batch-auctions-easyauction-sol-division-by-zero-85fd10212c97