Revert "Add yet-another-react-lightbox package and update .gitignore to exclude node_modules"

This reverts commit c92f4a5edd.

frontend/node_modules/flatpickr/dist/esm/utils/polyfills.js

@@ -0,0 +1,22 @@
+"use strict";
+if (typeof Object.assign !== "function") {
+    Object.assign = function (target) {
+        var args = [];
+        for (var _i = 1; _i < arguments.length; _i++) {
+            args[_i - 1] = arguments[_i];
+        }
+        if (!target) {
+            throw TypeError("Cannot convert undefined or null to object");
+        }
+        var _loop_1 = function (source) {
+            if (source) {
+                Object.keys(source).forEach(function (key) { return (target[key] = source[key]); });
+            }
+        };
+        for (var _a = 0, args_1 = args; _a < args_1.length; _a++) {
+            var source = args_1[_a];
+            _loop_1(source);
+        }
+        return target;
+    };
+}