Add support to Staking contract to separate operational from financial capabilities

[peterargue]

Issue To Be Solved

Currently, a single capability is used by node operators to interact with the Staking contract for all updates, including updating the node's hostname, staking/unstaking, and removing funds. This works fine for small or individual operators, but adds risk for larger operators that may have a team/automations that help manage their nodes.

Suggest A Solution

Instead of a single capability, create 2 or more separate capabilities that handle each of the types of accesses. For example, it could be broken down in the following way

1. Operational access - used to update the node's hostname and any other strictly operational changes. Operators could give access to this to an automated system or a team of operators
2. Staking/unstaking - used to commit new tokens, unstake tokens, or restake rewards, etc. All financial operations that don't involve withdrawing funds. This could be granted to a small number of highly trusted individuals to allow managing their fleet.
3. Withdrawing funds - used to withdraw unstaked funds. This would be kept securely in an HSM or cold storage with very restricted access.

By default, all 3 capabilities would be added to the node's staking account, but the operator would have the option to move/delegate them to different accounts.

[joshuahannan]

Made a small edit to your proposal to the second capability. This makes sense.

One question: I assume that most node operators and delegators are using the staking collection, so I am think that we just make these three new interfaces for the staking collection contract, or do you think we need to add the interfaces to both the core staking contract and the staking collection?

[peterargue]

I don't have a strong opinion on that. I think as long as there's a way for operators to delegate permission for each of those capabilities (particularly 1 & 2), either should be fine. Is it simple to switch to using the collection if you're currently using the core staking contract?

[joshuahannan]

yes, this transaction updates any account to use the staking collection, even if they are already using a different setup:
https://github.com/onflow/flow-core-contracts/blob/master/transactions/stakingCollection/setup_staking_collection.cdc

[joshuahannan]

I think the stable cadence upgrade would be a perfect place to introduce this feature since it is a great use case for entitlements. I'll try to get it added to the feature branch relatively soon