refactor: 💡 port confirmation service and components into core

addons/core/addon/components/pending-confirmations/index.hbs

@@ -0,0 +1,6 @@
+{{#each this.confirm.pending as |confirmation|}}
+  {{yield
+    confirmation
+    (fn this.accept confirmation)
+    (fn this.deny confirmation)}}
+{{/each}}

addons/core/addon/components/pending-confirmations/index.js

@@ -0,0 +1,38 @@
+import Component from '@glimmer/component';
+import { inject as service } from '@ember/service';
+import { action } from '@ember/object';
+
+/**
+ * A component that yields for each pending confirmation in the confirmations
+ * service, passing the confirmation instance, a confirm action, and a dismiss
+ * action. Useful for rendering confirm modals and awaiting user action.
+ */
+export default class PendingConfirmationsComponent extends Component {
+  // =services
+
+  @service confirm;
+
+  // =actions
+
+  /**
+   * Accepts the passed confirmation.
+   * @param {Confirmation} confirmation
+   * @return {Confirmation}
+   */
+  @action
+  accept(confirmation) {
+    confirmation.confirm();
+    return confirmation;
+  }
+
+  /**
+   * Denies the passed confirmation.
+   * @param {Confirmation} confirmation
+   * @return {Confirmation}
+   */
+  @action
+  deny(confirmation) {
+    confirmation.dismiss();
+    return confirmation;
+  }
+}