feat: add rpc for searching all invoices (#410)

* add rpc for searching all invoices

* update proto

Author: whoAbhishekSah

raystack/frontier/v1beta1/admin.proto

@@ -741,6 +741,17 @@ service AdminService {
     };
   }
 
+  rpc SearchInvoices(SearchInvoicesRequest) returns (SearchInvoicesResponse) {
+    option (google.api.http) = {
+      post: "/v1beta1/admin/invoices/search",
+      body: "query"
+    };
+    option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_operation) = {
+      tags: "invoice";
+      summary: "Search invoices across all organizations";
+    };
+  }
+
 }
 
 message ListAllUsersRequest {
@@ -1597,3 +1608,25 @@ message AdminCreateOrganizationRequest {
 message AdminCreateOrganizationResponse {
   Organization organization = 1;
 }
+
+message SearchInvoicesRequest {
+  RQLRequest query = 1;
+}
+
+message SearchInvoicesResponse {
+  message Invoice {
+    string id = 1;
+    int64 amount = 2;
+    string currency = 3;
+    string state = 4;
+    string invoice_link = 5;
+    google.protobuf.Timestamp created_at = 6;
+    string org_id = 7;
+    string org_name = 8;
+    string org_title = 9;
+  }
+
+  repeated Invoice invoices = 1;
+  RQLQueryPaginationResponse pagination = 2;
+  RQLQueryGroupResponse group = 3;
+}