Describe the changes
Before:
Each network service (HTTP, Gossip, Reth) required explicit public_ip and bind_ip configuration in TOML files.

After:
Added NetworkDefaults struct and NetworkConfigWithDefaults trait. Services inherit IPs from [network_defaults] section

Changes

Configuration Types (crates/types/src/config/node.rs)

• Added NetworkDefaults struct with public_ip and bind_ip fields
• Added NetworkConfigWithDefaults trait with fallback methods public_ip() and bind_ip()
• Changed GossipConfig, HttpConfig, RethNetworkConfig IP fields from String to Option<String>
• Implemented NetworkConfigWithDefaults for all 3 config structs
• Added network_defaults: NetworkDefaults field to NodeConfig

Config File Templates

• Added [network_defaults] section to mainnet_config.toml and testnet_config.toml
• Updated docker config files with same pattern

Related Issue(s)
Please link to the issue(s) that will be closed with this PR.

Checklist

• Tests have been added/updated for the changes.
• Documentation has been updated for the changes (if applicable).
• The code follows Rust's style guidelines.

Additional Context
Add any other context about the pull request here.