vuetify: Ability to set error state for text field via parameter

I think rules prop of v-text-field is unnecessary functionality, because in most cases we have to validate our form values not in text fields components. Just imagine if you need to disable submit button before all you inputs do not have errors. With current v-text-field api you have to run validations twice. So, I suggest add new boolean prop error to v-text-field. If error is true the field should look like field with error.