feat(cbh): add postPaid mode to create instance

[jnzr123]

What this PR does / why we need it:
add postPaid mode to create instance
Which issue this PR fixes:
(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)
fixes #xxx

Special notes for your reviewer:

Release note:

PR Checklist

• Tests added/passed.

TF_ACC=1 go test "./huaweicloud/services/acceptance/cbh" -v -coverprofile="./huaweicloud/services/acceptance/cbh/cbh_coverage.cov" -coverpkg="./huaweicloud/services/cbh" -run TestAccCBHInstance_basic -timeout 360m -parallel 10
=== RUN   TestAccCBHInstance_basic
=== PAUSE TestAccCBHInstance_basic
=== CONT  TestAccCBHInstance_basic
--- PASS: TestAccCBHInstance_basic (2099.39s)
PASS
coverage: 22.5% of statements in ./huaweicloud/services/cbh

• Documentation updated.

• Schema updated.

• CheckDeleted.

  • a. During query operation (Read Context)
    aa. Resource not found
    >>>>>> Paste the screenshot here <<<<<<

  • b. During delete/disassociate/unbind operation (Delete Context)
    ba. Resource not found
    >>>>>> Paste the screenshot here <<<<<<

[deer-hang]

Please keep the Required description.

[deer-hang]

            // The current network environment only supports prepaid CBH. However, the HCSO environment supports CBH with prepaid and postpaid. Hiding postpaid capabilities as internal features.
			"period_unit": {
				Type:     schema.TypeString,
				Optional: true,
				ForceNew: true,
				ValidateFunc: validation.StringInSlice([]string{
					"month", "year",
				}, false),
				Description: utils.SchemaDesc("Specifies the charging period unit of the instance.", utils.SchemaDescInput{Required: true}),
			},

[deer-hang]

Same to field period_unit.

[deer-hang]

This method is poorly readable and is recommended for optimization.

	respBody, err := createCBHInstance(client, d, cfg)
	if err != nil {
		return diag.FromErr(err)
	}

    var instanceID string
   if d.Get("charging_mode").(string) == "prePaid" {
        instanceID, err := waitingPostpaidCBHComplete()
  } else {
        instanceID, err := utils.PathSearch("instance_id", respBody, "").(string)
  }

  d.SetId(instanceID)
  if err := waitingForCBHInstanceActive(ctx, client, d, d.Timeout(schema.TimeoutCreate)); err != nil {
		return diag.Errorf("error waiting for CBH instance (%s) creation to active: %s", d.Id(), err)
  }
  

[deer-hang]

No documentation for postpaid CBH was found on the official website, and there is a lack of logical support.