feat: add type in schema Port to support multiple clouds (#34)

models/samples/helloworld/base/base.k

@@ -51,6 +51,7 @@ helloworld: ac.AppConfiguration {
         replicas: 2
         ports: [
             n.Port {
+                type: "aliyun"
                 port: 80
                 targetPort: 8080
                 public: True

models/samples/wordpress/base/base.k

@@ -28,6 +28,7 @@ wordpress: ac.AppConfiguration {
         replicas: 2
         ports: [
             n.Port {
+                type: "aliyun"
                 port: 80
                 public: True
             }

models/schema/v1/workload/network/port.k

@@ -4,6 +4,8 @@ schema Port:
 
     Attributes
     ----------
+    type: "aliyun" | "aws", default is Undefined, optional.
+        The specific cloud vendor that provides load balancer, works when public is True.
     port: int, default is 80, required.
         The exposed port of the Service.
     targetPort: int, default is Undefined, optional.
@@ -18,13 +20,17 @@ schema Port:
     import models.schema.v1.workload.network as n
 
     port = n.Port {
+        type: "aliyun"
         port: 80
         targetPort: 8080
         protocol: "TCP"
         public: True
     }
     """
 
+    # The specific cloud vendor that provides load balancer, works when public is True.
+    type?:                      "aliyun" | "aws"
+
     # The exposed port of the Service.
     port:                       int = 80
 
@@ -37,7 +43,7 @@ schema Port:
     # Public defines whether to expose the port through Internet.
     public:                     bool = False
 
-
     check:
+        type if public, "type must exist when public is True"
         1 <= port <= 65535, "port must be between 1 and 65535, inclusive"
         1 <= targetPort <= 65535 if targetPort, "targetPort must be between 1 and 65535, inclusive"