Added validators for polling source + refactor + delete method + update method
Added validators for polling source + refactor + delete method + update method

shinitiandrei/terraform-provider-sumologic,shinitiandrei/terraform-provider-sumologic,erikvanbrakel/terraform-provider-sumologic,erikvanbrakel/terraform-provider-sumologic,shinitiandrei/terraform-provider-sumologic,erikvanbrakel/terraform-provider-sumologic