CDN: Add Support for "needs-cloudflare-cert"

[danaelhe]

Address #1086

In order to have Cloudflare generate a certificate, certificate_id must be set to the value "needs-cloudflare-cert" in our API.

In the Terraform provider certificate_name is passed in instead of a certificate_id (we've deprecated certificate_id attribute in favor of certificate_name for digitalocean_cdn because when the certificate type is lets_encrypt, the certificate ID will change on renewal (after 3 months)), we use the name to look up the id and then set that id to certificate_id.....hence the certificate_id will not be needs-cloudflare-cert here:

	if name, nameOk := d.GetOk("certificate_name"); nameOk {
		certName := name.(string)
		if certName != "" {
			cert, err := certificate.FindCertificateByName(client, certName)
			if err != nil {
				return diag.FromErr(err)
			}

			cdnRequest.CertificateID = cert.ID
		}

Added logic to check if needs-cloudflare-certis passed into certificate_name to set that as the certificate_id

[danaelhe]

Hey @itssimon - could you give this a try?

[andrewsomething]

👍 Think this is a great workaround for the moment.

[andrewsomething]

🚀