applied the comments regarding chord progression, scale suggestions and UI/UX changes

Delete backend/presets/sample-track

some minor UI changes: adding the playback functionality for the chosen section with no key and bpm change and replacing the upload new with choose a different song

Replace OGG stems with length-corrected re-encodes at q9

Add preset tracks with OGG stems and metadata overrides for key/BPM detection

implemented some UI changes including adding a knob for pan and reverb, changing the UI of the key and bpm modification and changing the appearance of the detected key and bpm and removed some dev

Add IndexedDB preset caching with background prefetch

add demo preset system with sample track

fixed the playback bug

increasing the speed of uploading to the server

deleted the server and client side decoding so the play back is ready instantly after loading the stems

added the looping function and changing the key and bpm of portion of the song

fixed the upload size error message

adding post processing and increasing the number of co-current processes

updated the MVP-Initial upload