Remote Keymanager API (Web3Signer): List,Import, and Delete

[james-prysm]

🦄 Feature Tracking

Current status (opt-in or opt-out):

Opt-in feature flag name:

Opt-out feature flag name:

Feature Description

As a node operator, I would like to be able to list, import, and delete public keys defined for Prysm's Web3Signer feature.
The definitions of these APIs are consistent across all client teams and listed here. This will enable institutions to migrate keys from clients via web3signer as well as

Tasks

• allow users to start Prysm without public keys defined for web3signer
• stall Prsym if no keys are used while using web3signer
• log note that this API/feature is only enabled for web3signer and not Prysm's native remote signer
• Remote Keymanager API List
• Remote Keymanager API Import
• Remote Keymanager API Delete

This issue should be closed after all of the above tasks are complete.