Adds 4 new fields to the extension tab

1. Checkbox To enable this extension
2. A textfield to take an import package name
3. A textfield to take a parent class name (only applies to the topmost level)
4. A textfield to take properties to exclude from the output class (which actually would be the common properties you have in your parent class), comma-separated

The output should be like as follows

import $import_package

data class(
... // properties not given as input
) : $parent class

Do note that the inputs taken are just texts and are used as texts.

Also bumped kotlin version to 1.5.30.