feat(frontier): replace an existing policy

- ReplacePolicy will take an id of the existing policy and
replace it with the provided policy body.

Signed-off-by: Kush Sharma <thekushsharma@gmail.com>

Author: kushsharma

raystack/frontier/v1beta1/frontier.proto

@@ -951,6 +951,18 @@ service FrontierService {
     };
   }
 
+  rpc ReplacePolicy(ReplacePolicyRequest) returns (ReplacePolicyResponse) {
+    option (google.api.http) = {
+      post: "/v1beta1/policies/{id}/replace",
+      body: "*"
+    };
+    option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_operation) = {
+      tags: "Policy";
+      summary: "Replace policy";
+      description: "Deletes an existing policy and create new.";
+    };
+  }
+
   // Relations
   rpc CreateRelation(CreateRelationRequest) returns (CreateRelationResponse) {
     option (google.api.http) = {
@@ -2323,6 +2335,15 @@ message DeletePolicyRequest {
 
 message DeletePolicyResponse {}
 
+message ReplacePolicyRequest {
+  string id = 1;
+  PolicyRequestBody body = 2;
+}
+
+message ReplacePolicyResponse {
+  Policy policy = 1;
+}
+
 message RelationRequestBody {
   reserved 2, 5;