TIP-121a (cont.): Sell last LUSD, Timelock and Role Cleanup + La Tribu Clawback

This proposal is a continuation of the first stage of TIP-121 (https://tribe.fei.money/t/tip-121-proposal-for-the-future-of-the-tribe-dao/4475).

This proposal sells the last ~100k LUSD for DAI using a curve swap.

It also claws back ~1M FEI and TRIBE from La Tribu, closing out the last DAO funded initiative.

It disables the PCV Sentinel Aave/Compound Fei withdrawal guard as the Fei has been withdrawn.

It cleans up the timelocks and deprecated roles in the system, where any of these changes can be reversed in a further DAO vote if needed.