Backend MP4 conversion (#23)

* ADD conversion queue

* ADD RemuxService for MP4 conversion

* REMOVE unused conversion queue

* REORGANISE Job-related classes

* ADD Job stages

* REVERT to old commit, using Spring Async instead

* ADD asynchronous processing for video tasks

* PATCH and streamline progress tracking

* ADD asynchronous video processing and job restructuring

* REFACTOR job service method

* ADD job remux functionality

* ADD remuxing endpoint

* PATCH complete flag not updating in API response

* ADD progress type in frontend

* ADD reset functionality for job status

* PATCH missing progress bar for subsequent exports

* REDESIGN settings box

* ADD tracking video file conversion in frontend

* PATCH extension bug

* REMOVE autowired decorator

frontend/src/pages/ClipEdit.tsx

@@ -49,11 +49,13 @@ const ClipEdit = () => {
     const pollProgress = async (id: string, intervalId: number) => {
         getProgress(id)
             .then((progress) => {
-                setProgress(progress);
+                setProgress(progress.process.progress);
 
-                if (progress >= 1) {
+                if (progress.process.complete) {
                     clearInterval(intervalId);
                     setDownloadable(true);
+                } else {
+                    setDownloadable(false)
                 }
         })
             .catch((err: Error) => {