update remove liquidity; add withdraw shares to state

[dpaiton]

remove liquidity needs some updates:

• add redeem withdraw shares functionality to hyperdrivepy
• remove liquidity in hyperdrivepy has the incorrect return type
  • the rust version returns two values, but the python version returns a single value
• track withdraw shares total supply (aka withdraw_shares_asset_id balance) in State
  • this is required for us to estimate PnL (or mock closing LP) in simulation mode
• use state to access as many of the variables required in the fn signature
  • aka review the fns in remove.rs and ensure that the pattern for signatures matches everywhere else