1. Use `this.` instead of `{{action}}` where applicable
2. Use `{{fn}}` instead of `@actionParam` where applicable
3. Use non-`@` versions of class/type/tabindex/aria-controls/aria-expanded
4. Remove `btn` class (it's added automatically to all DButtons)
5. Remove `type="button"` (it's the default)
6. Use `concat-class` helper
The `tagName` argument is now deprecated. This commit uses a codemod (https://github.com/discourse/discourse-ember-codemods/tree/main/transforms/extract-plugin-outlet-tagname) to automatically remove the `@tagName` from all PluginOutlet invocations, and create a matching wrapper element so that the HTML structure is unchanged. We may want to remove some/all of these wrappers entirely in future, but that would be a riskier change which we should tackle on a case-by-case basis.
1. The events table had broken styling, making each row overflow
2. It had confusing routes: `/:id` for "edit" and `/:id/events` for "show" (now it's `/:id/edit` and `/:id` respectively)
3. There previously was an unused backend action (`#edit`) - now it is used (and `web_hooks/:id/events` route has been removed)
4. There was outdated/misplaced/duplicated CSS
5. And more
