* Companion for Decouple Staking and Election - Part 3: Signed Phase
https://github.com/paritytech/substrate/pull/7910
* remove some config types
* allow up to 5 signed submissions on polkadot and kusama
* signed phase is equal induration to unsigned phase
* use chain defaults for base and per-byte deposits; >= 16 SignedMaxSubmissions
* use a small but non-trivial solution reward
* reduce signed deposit per byte fee
* reduce signed reward, adjust polkadot expected soln size
* copy submit benchmark from substrate
* demo calculating an appropriate fee for the signed reward
Unfortunately, this doesn't work: it needs to be a constant function,
and AFAIK there's no way to make a trait method constant.
* SignedRewardBase is 1.5x the fee to submit a signed solution
* all chains use deposit byte of base per 50k
* update Substrate
* cargo update -p pallet-election-provider-multi-phase
Co-authored-by: parity-processbot <>
Zeke Mostov