Mithril client

[johnalotoski]

Overview:

• Adds a mithril client for nixosConfigurations, process-compose cardano-node processes and cardano-node entrypoint

Details:

• Adds a mithril client and signer packages, iohk-nix mithril input
• Adds a cardano-node mithril client for nixosConfigurations using profile-cardano-node-group nixosModule
• Adds a process-compose cardano-node mithril client
• Adds a cardano-node entrypoint mithril client, replacing the prior snapshot entrypoint functionality

Default Mithril Behavior:

• Mithril client will bootstrap automatically on preview and preprod environments
• Mithril client for mainnet is expected to be enabled in the near future
• nixosConfigurations can disable mithril bootstrapping with the config.services.cardano-node.enableMithrilClient option
• process-compose can disable mithril bootstrapping with the MITHRIL_DISABLE or MITHRIL_DISABLE_$ENV env vars
• cardano-node entrypoint can disable mithril bootstrapping with the MITHRIL_DISABLE env var