Improve loops & fix cpp check warning

- This commit improves certain while loops to range based for loops.

- This commit also fixes the cppcheck warning that mentions about
  performance issues when using postfix operators on non-primitive
  types.

Tested By:
- A function is unittested.
- GET on both EthernetInterfaces & certificate service
  looks good without any issues.

Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: I85420f7bf9af45a97e1a93b916f292c2516f5802
diff --git a/redfish-core/lib/certificate_service.hpp b/redfish-core/lib/certificate_service.hpp
index 5dc1e1f..81d9d05 100644
--- a/redfish-core/lib/certificate_service.hpp
+++ b/redfish-core/lib/certificate_service.hpp
@@ -516,7 +516,7 @@
         std::string_view::iterator tokenBegin = i;
         while (i != value.end() && *i != '=')
         {
-            i++;
+            ++i;
         }
         if (i == value.end())
         {
@@ -524,11 +524,11 @@
         }
         const std::string_view key(tokenBegin,
                                    static_cast<size_t>(i - tokenBegin));
-        i++;
+        ++i;
         tokenBegin = i;
         while (i != value.end() && *i != ',')
         {
-            i++;
+            ++i;
         }
         const std::string_view val(tokenBegin,
                                    static_cast<size_t>(i - tokenBegin));
@@ -559,7 +559,7 @@
         // skip comma character
         if (i != value.end())
         {
-            i++;
+            ++i;
         }
     }
 }