Increase DOGE staking limit

Currently DOGE staking is limited to 1,000 units. Though this is an arbitrary limit for a blockchain contract since a user can create an unlimited number of account and thus bypass this limit.

At the end of the day, this current limit is just cumbersome for any user with more 1,000 DOGE which is a very common use case.

Please consider increasing the limit to one of the following bounds.