off-Discord validator messaging

[dynst]

Is your feature request related to a problem? Please describe.

Communicating with other validators as a validator effectively requires linking your permanent identity key with your Discord account, with all the privacy issues that implies.

Describe the solution you'd like

A convenient, clearly documented way to communicate using only a signature from a governance subkey and a way to broadcast it. Any of these might work:

• An on-chain transaction for validators to publish a cleartext message to the chain. (Might be good for justifying their public ValidatorVote?)
• A pcli command that conveniently sends an encrypted memo in a transaction to all other active validators, who can verify which gov subkey sent it. (Useful for more sensitive security concerns?)
• A pcli command that signs an off-chain message and uploads it to a service that publishes it publicly somewhere (including, probably, to the Discord - this communication method isn't mandatory).

Describe alternatives you've considered

Keep the status quo, or just create a Matrix room with a bridge to the Discord.

Additional context

THORChain has something like this: they operate a validator-relay-bot in their Discord that relays signed, off-chain messages from validators. [1] [2]