feat: add ds records and name servers resources for domains

[App13Pie]

Description

Added two resources for OVH domains:

• ovh_domain_name_servers: Resource to set external name servers for a domain.
• ovh_domain_ds_records: Resource to set ds_records for a domain

TODO: I haven't updated the documentation.

Fixes #146 (issue)

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

I created a public zone on GPC Cloud DNS to have valid values to pass down to the below tests.

You'll have to export these environment variables:

export OVH_ZONE_TEST="..."
export OVH_DOMAIN_NS1_HOST_TEST="..."
export OVH_DOMAIN_NS1_IP_TEST="..."
export OVH_DOMAIN_NS2_HOST_TEST="..."
export OVH_DOMAIN_NS3_HOST_TEST="..."
export OVH_DOMAIN_DS_RECORD_ALGORITHM_TEST="..."
export OVH_DOMAIN_DS_RECORD_PUBLIC_KEY_TEST="..."
export OVH_DOMAIN_DS_RECORD_TAG_TEST="..."

• Test A: make testacc TESTARGS="-run TestAccDomainNameServers_Basic"

Test Configuration:

• Terraform version: terraform version: Terraform v1.10.5
• Existing HCL configuration you used:

resource "ovh_domain_name_servers" "test" {
	domain = "test.ovh"

	servers {
		host = "ns-cloud-a1.googledomains.com"
		ip = "216.239.32.106"
	}

	servers {
		host = "ns-cloud-a2.googledomains.com"
		ip = ""
    }
}

• Test B: make testacc TESTARGS="-run TestAccDomainDsRecords_Basic"

Test Configuration:

• Terraform version: terraform version: Terraform v1.10.5
• Existing HCL configuration you used:

resource "ovh_domain_ds_records" "test" {
	domain = "test.ovh"

	ds_records {
		algorithm = "RSASHA256"
		flags = "KEY_SIGNING_KEY"
		public_key = "YOUR_PUBLIC_KEY"
		tag = 12345
	}
}

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings or issues
• I have added acceptance tests that prove my fix is effective or that my feature works
• New and existing acceptance tests pass locally with my changes
• I ran succesfully go mod vendor if I added or modify go.mod file