Use more kartik's class in generated code

[devleaks]

Hello,

In order to make generated code more homogenous, would it be possible to replace yii\grid\SerialColumn and yii\grid\ActionColumn with kartik\grid\SerialColumn and kartik\grid\ActionColumn. Kartik's versions offer numerous more customization options. Thank you.

PS: Since I'm using most of Kartik's gridview and forms, this template is my Yii2 CRUD Generator default. Thank you for the good work.