Add API for Character through AJAX and select2

[ianmandap]

Select2 with Rails 6:
https://dev.to/mainstreet/rails-6-stimulus-and-select2-4901
https://stackoverflow.com/questions/58780725/getting-jquery-and-bootstrap-to-work-with-rails-6 (With Webpacker insights)
https://stackoverflow.com/questions/57698025/select2-with-stimulus-and-webpacker-in-rails-6 window.$ = $ worked
https://stackoverflow.com/a/49722514/15233426 (Other users do this: select2($); and later $('select').select2();

Adding Select2 options:
https://rails-select2-example.herokuapp.com/

API:
https://www.dnd5eapi.co/docs/#intro

jQuery:
https://blog.corsego.com/install-jquery-in-rails-6
https://www.yogihosting.com/example-jquery-ajax-call-api/