Added a very basic modal on part info page for changing part instock

Related to issue #201

assets/controllers/pages/part_withdraw_modal_controller.js

@@ -0,0 +1,41 @@
+import {Controller} from "@hotwired/stimulus";
+import {Modal} from "bootstrap";
+
+export default class extends Controller
+{
+    connect() {
+
+
+        this.element.addEventListener('show.bs.modal', event => this._handleModalOpen(event));
+
+        //Register an event to remove the backdrop, when the form is submitted
+        const form = this.element.querySelector('form');
+        form.addEventListener('submit', event => {
+            //Remove the backdrop
+            document.querySelector('.modal-backdrop').remove();
+        });
+    }
+
+    _handleModalOpen(event) {
+        // Button that triggered the modal
+        const button = event.relatedTarget;
+
+        const amountInput = this.element.querySelector('input[name="amount"]');
+
+        // Extract info from button attributes
+        const action = button.getAttribute('data-action');
+        const lotID = button.getAttribute('data-lot-id');
+        const lotAmount = button.getAttribute('data-lot-amount');
+
+        //Set the action and lotID inputs in the form
+        this.element.querySelector('input[name="action"]').setAttribute('value', action);
+        this.element.querySelector('input[name="lot_id"]').setAttribute('value', lotID);
+
+        //For adding parts there is no limit on the amount to add
+        if (action == 'add') {
+            amountInput.removeAttribute('max');
+        } else { //Every other action is limited to the amount of parts in the lot
+            amountInput.setAttribute('max', lotAmount);
+        }
+    }
+}