[MACRO] Permissioned Stake Table follow up work

[sveitser]

We merged an initial version of the permissioned stake table contract, some rough edges remain:

• Consider enforcing a maximum number of stakers in the contract. It might be best to set this the same as the stake table capacity. Should check with @mrain or @alxiong.
• Don't require entire NodeInfo struct when removing stakers from permissioned stake table contract #2419
• Consider a better name for the NodeInfo type in the contract.
• Consider validating BLS key in contract. It's not clear if this is worth it. It can prevent some errors but we can also do that by doing this validation in scripts instead of the contract.
• Documentation for new contract: at least some solidity code docs and a README file describing what to pay attention to during deployment and interaction with the contract.
• Multisig upgrade of permissioned stake table #2493