Use obviously invalid addresses rather than devkeys unles --use-dev-mnemonic is specified

[mslipper]

Right now, running op-deployer init generates an intent file with addresses derived from the test mnemonic. This creates a valid intent out-of-the-box, but it can be dangerous since users likely do not know that these addresses are derived from a public mnemonic. To protect users, we should:

• Use 0xdeaddeaddead addresses for the fee vaults and Superchain ownership addresses when running init
• Use the devkeys addresses when users pass --use-dev-mnemonic on the command line. This way users acknowledge that the devkey addresses should not be used on a live chain.