feat: improve SQL results formatting in Lua

sbroad-cartridge/src/router.lua

 require('strict').on()
 require('sbroad')
 require('sbroad.core-router')
+local helper = require('sbroad.helper')
 
 local cartridge = require('cartridge')
 
@@ -65,7 +66,7 @@ local function trace(query, params, context, id)
         return nil, parser_res
     end
 
-    return parser_res[1]
+    return helper.format_result(parser_res[1])
 end
 
 local function execute(query, params)
@@ -79,7 +80,7 @@ local function execute(query, params)
         return nil, parser_res
     end
 
-    return parser_res[1]
+    return helper.format_result(parser_res[1])
 end
 
 return {

sbroad-core/src/helper.lua

@@ -6,6 +6,22 @@ local function module_name()
     end
 end
 
+local function format_result(result)
+    local formatted = {}
+    if result['metadata'] ~= nil then
+	formatted.metadata = setmetatable(result.metadata, { __serialize = nil })
+    end
+    if result['rows'] ~= nil then
+	formatted.rows = setmetatable(result.rows, { __serialize = nil })
+    end
+    if result['metadata'] == nil and result['rows'] == nil then
+	formatted = setmetatable(result, { __serialize = nil })
+    end
+
+    return formatted
+end
+
 return {
     module_name = module_name,
+    format_result = format_result,
 }