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

This reverts commit c92f4a5edd.

frontend/node_modules/react-dropzone/examples/validator/README.md

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+By providing `validator` prop you can specify custom validation for files.
+
+The value must be a function that accepts File object and returns null if file should be accepted or error object/array of error objects if file should be rejected.
+
+```jsx harmony
+import React from 'react';
+import {useDropzone} from 'react-dropzone';
+
+const maxLength = 20;
+
+function nameLengthValidator(file) {
+  if (file.name.length > maxLength) {
+    return {
+      code: "name-too-large",
+      message: `Name is larger than ${maxLength} characters`
+    };
+  }
+
+  return null
+}
+
+function CustomValidation(props) {
+  const {
+    acceptedFiles,
+    fileRejections,
+    getRootProps,
+    getInputProps
+  } = useDropzone({
+    validator: nameLengthValidator
+  });
+
+  const acceptedFileItems = acceptedFiles.map(file => (
+    <li key={file.path}>
+      {file.path} - {file.size} bytes
+    </li>
+  ));
+
+  const fileRejectionItems = fileRejections.map(({ file, errors }) => (
+    <li key={file.path}>
+      {file.path} - {file.size} bytes
+      <ul>
+        {errors.map(e => (
+          <li key={e.code}>{e.message}</li>
+        ))}
+      </ul>
+    </li>
+  ));
+
+  return (
+    <section className="container">
+      <div {...getRootProps({ className: 'dropzone' })}>
+        <input {...getInputProps()} />
+        <p>Drag 'n' drop some files here, or click to select files</p>
+        <em>(Only files with name less than 20 characters will be accepted)</em>
+      </div>
+      <aside>
+        <h4>Accepted files</h4>
+        <ul>{acceptedFileItems}</ul>
+        <h4>Rejected files</h4>
+        <ul>{fileRejectionItems}</ul>
+      </aside>
+    </section>
+  );
+}
+
+<CustomValidation />
+```
+