Proto/Adaptive Inflation: add baker parameters

We want the baker to be able to set 2 parameters:

• their own staking_over_baking_limit
  • ideally a Q but probably easier to just use a uint32 of 1/1_000_000s.
  • should be >= 0 but let's not worry about a value that would be over the global staking_over_baking_limit
  • see Frozen_deposits_limit in Storage
  • default (unset) is 0
• their baking_over_staking_edge
  • ideally a Q but... (same thing, maybe a value between 0 and 1_000_000_000)
  • should mean a value between 0 and 100%
  • same thing for storage
  • default (unset) is whatever
• both parameters must take preserved_cycles to be taken into account
  • probably better to look at Pending_consensus_key for the storage and cleanup
• setting them via a pseudo-transfer of the baker to themself
  • see "stake" in Apply
  • both are set at the same time (forces baker to care about both)
  • entrypoint named set_delegate_parameters?
  • allowed for delegates only
  • amount must be zero
  • parameter is a tuple pair (nat, pair (nat, unit)) (unit may allow adding more parameters later more easily)