Change 2-letter upload codes to more meaningful names

[EricClaeys]

When uploading files, the upload.sh script uploads to a temporary file name, then move that temporary file to the final destination. The temporary file name is passed to upload.sh as a 2-letter string, and a random number is appended. The 2-letter strings indicate what type of file is being uploaded:

• TL = Time Lapse
• NI = Notification Image
• ST = StarTrails
  etc.
  Those temporary files sometimes remain on the user's web server due to bugs.
  To aid in debugging, the 2-letter strings should be more meaningful, for example "ST" should be "StarTrails".