update SDTController to vote on stakedao gauges

[thetechnocratic]

from scoopy:

hey, found something that I want added to the stakedao controller, the vote_for_gauge_weights function. it will allow us to vote on the stakedao gauges, which will give us more sdt rewards for our sdCRV staked. Here's their gauge contract for reference.

https://etherscan.io/address/0x75f8f7fa4b6da6de9f4fe972c811b778cefce882#writeContract