renamed "attachment" to "file" for consistency

src/public/javascripts/services/file.js

@@ -0,0 +1,29 @@
+import noteDetailService from "./note_detail.js";
+import treeService from "./tree.js";
+import server from "./server.js";
+
+function uploadFile() {
+    $("#file-upload").trigger('click');
+}
+
+$("#file-upload").change(async function() {
+    const formData = new FormData();
+    formData.append('upload', this.files[0]);
+
+    const resp = await $.ajax({
+        url: baseApiUrl + 'files/upload/' + noteDetailService.getCurrentNoteId(),
+        headers: server.getHeaders(),
+        data: formData,
+        type: 'POST',
+        contentType: false, // NEEDED, DON'T OMIT THIS
+        processData: false, // NEEDED, DON'T OMIT THIS
+    });
+
+    await treeService.reload();
+
+    await treeService.activateNode(resp.noteId);
+});
+
+export default {
+    uploadFile
+}