Feature Request: Warn of people try to use public RPCs to deploy programs

[jacobcreech]

Problem

When developers are deploying programs, they sometimes try using the public RPCs thinking they're good enough instead of obtaining production infra. This leads to a bad experience and devs thinking Solana is bad

Proposed Solution

Give a helpful warning that deployments will take ages if they use public RPCs for Mainnet and point to obtaining a production RPC. Could use a link such as solana.com/rpc.