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

This reverts commit c92f4a5edd.

frontend/node_modules/react-dropzone/examples/theme.css

@@ -0,0 +1,37 @@
+.container {
+  display: flex;
+  flex-direction: column;
+  font-family: sans-serif;
+}
+
+.container > p {
+  font-size: 1rem;
+}
+
+.container > em {
+  font-size: .8rem;
+}
+
+.dropzone {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  padding: 20px;
+  border-width: 2px;
+  border-radius: 2px;
+  border-color: #eeeeee;
+  border-style: dashed;
+  background-color: #fafafa;
+  color: #bdbdbd;
+  outline: none;
+  transition: border .24s ease-in-out;
+}
+
+.dropzone:focus {
+  border-color: #2196f3;
+}
+
+.dropzone.disabled {
+  opacity: 0.6;
+}