cli: Enhance NTT CLI to streamline rate limit configuration

[evgeniko]

Improve the NTT CLI workflow to allow direct rate limit configuration through CLI commands in setting rate limits:

Proposed CLI enhancements:

• ntt limit init
  Initialize rate limits for all configured chains with correct decimal precision

• ntt limit set <chain> --outbound <amount> --inbound <chain> <amount>
  Set specific rate limits with automatic decimal adjustment

[kcsongor]

I like the ntt limit set idea. Instead of a separate init step though, we could just populate those 0 fields when adding a chain, basically avoiding having to run ntt pull straight after doing so.