Polishing v3 pool creator

[x] Figure out successful pool initialization end state
[x] Figure out strategy for setting minBptAmountOut on pool init
[x] If more than 2 tokens, allow user to remove a token
[x] Figure out strategy for user potentially network switching during pool config and/or tx steps
[x] Figure out permit2 for pool init to reduce # of txs required
[ ] Warning if users joining with token amounts that deviate from weights?
[x] Ability to resume some way through the transaction flow?
[ ] Auto fill rate provider using data from API
[ ] Warn if user enters rate provider that hasnt been reviewed
[ ] Figure out weight locking similar to beethoven
[ ] Test pool creation with tokens that have rate provider
[ ] Explore preset options feature similar to curve (would be good for hooks)
[x] Decide if state should be kept in local storage or if it's better to let it reset on page refresh
[ ] Improve / add more input validations
[ ] Improve pool preview
[ ] Improve styles

balancer / pool-creator