Add autosize textarea

[drnic]

yarn add autosize

# app/javascript/controllers/autosize_textarea_controller.js
import { Controller } from "@hotwired/stimulus"
import autosize from "autosize"

export default class extends Controller {
  connect() {
    autosize(this.element)
  }
}

Update scaffold generator to use it for text_area:

    <%= f.text_area :body, class: "form-control", data: {controller: "autosize-textarea"} %>