Redeployment of the Base Router for V3.
Contains Router for basic, single step operations (e.g., pool initialization, add, remove, swap).
The original router can still be used. The difference is this version saves the sender (i.e., uses the saveSender modifier) on initialization as well as on add liquidity operations, enabling pools to verify the sender on liquidity operations (e.g., to enforce a single-LP, as in liquidity bootstrapping or treasury management pools).
There were also other changes to the Router contract and inheritance hierarchy since the original deployment (e.g., introduction of WethLib and SenderGuard in RouterCommon), but these are refactors designed to make router development easier (e.g., for the AggregatorRouter), and are not semantic or interface changes.