feat(DDS): import DDS resource, unit test and document.

### resourceName: resource_flexibleengine_dds_parameter_template

docs/resources/dds_parameter_template.md

@@ -0,0 +1,93 @@
+---
+subcategory: "Document Database Service (DDS)"
+---
+
+# flexibleengine_dds_parameter_template
+
+Manages a DDS parameter template resource within FlexibleEngineCloud.
+
+## Example Usage
+
+```hcl
+variable "name" {}
+variable "parameter_values" {}
+variable "node_type" {}
+variable "node_version" {}
+
+resource "flexibleengine_dds_parameter_template" "test"{
+  name             = var.name
+  parameter_values = var.parameter_values
+  node_type        = var.node_type
+  node_version     = var.node_version
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `region` - (Optional, String, ForceNew) Specifies the region in which to create the resource.
+  If omitted, the provider-level region will be used. Changing this parameter will create a new resource.
+
+* `name` - (Required, String) Specifies the parameter template name.
+  The value must be 1 to 64 characters, which can contain only letters, digits, hyphens (-),
+  underscores (_), and periods (.).
+
+* `node_type` - (Required, String, ForceNew) Specifies the node type of parameter template node_type. Valid value:
+  + **mongos**: the mongos node type.
+  + **shard**: the shard node type.
+  + **config**: the config node type.
+  + **replica**: the replica node type.
+  + **single**: the single node type.
+
+  Changing this parameter will create a new resource.
+
+* `node_version` - (Required, String, ForceNew) Specifies the database version.
+  The value can be **4.2**, **4.0** or **3.4**.
+
+  Changing this parameter will create a new resource.
+
+* `parameter_values` - (Optional, Map) Specifies the mapping between parameter names and parameter values.
+  You can customize parameter values based on the parameters in the default parameter template.
+
+* `description` - (Optional, String) Specifies the parameter template description.
+  The description must consist of a maximum of 256 characters and cannot contain the carriage
+  return character or the following special characters: >!<"&'=.
+
+## Attribute Reference
+
+In addition to all arguments above, the following attributes are exported:
+
+* `id` - The resource ID.
+
+* `parameters` - Indicates the parameters defined by users based on the default parameter templates.
+  The [parameters](#DdsParameterTemplate_Parameter) structure is documented below.
+
+<a name="DdsParameterTemplate_Parameter"></a>
+The `parameters` block supports:
+
+* `name` - Indicates the parameter name.
+
+* `value` - Indicates the parameter value.
+
+* `description` - Indicates the parameter description.
+
+* `type` - Indicates the parameter type. The value can be integer, string, boolean, float, or list.
+
+* `value_range` - Indicates the value range.
+
+* `restart_required` - Indicates whether the instance needs to be restarted.
+  + If the value is **true**, restart is required.
+  + If the value is **false**, restart is not required.
+
+* `readonly` - Indicates whether the parameter is read-only.
+  + If the value is **true**, the parameter is read-only.
+  + If the value is **false**, the parameter is not read-only.
+
+## Import
+
+The DDS parameter template can be imported using the `id`, e.g.
+
+```shell
+terraform import flexibleengine_dds_parameter_template.test <tempalate_id>
+```