added fix for the issue #328

[sundaram2021]

The Terraform provider needed to set the create_default_rules flag based on whether the firewall was created with default rules, especially during terraform import.

I added a function in the Civo SDK (firewall.go) that checks whether a firewall is using default rules by comparing the actual firewall rules with predefined default rules (e.g., allowing SSH, HTTP, and HTTPS traffic).

In the Terraform provider (resource_firewall.go), I modified the logic to call this function during resource creation and import. This ensures that the create_default_rules flag is accurately set in the Terraform state based on the current firewall rules.

Now, when a firewall is created or imported, the provider checks if default rules are used and sets the create_default_rules flag accordingly, preventing misconfiguration and ensuring consistency between the actual firewall state and Terraform's state.