Improve Post-Processing

[andi34]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request? (put an "x" next to an item)

• Bug fixes
• Others

What changes did you make? (Give an overview)

• Bug fixes
  • collage:
    • always respect the time an image on continuous collage is visible (before, post-processing started without showing the last image of the collage)
    • Apply defined effect(s) and/or filter to the single images instead of the final collage
  • config:

    • temporary remove numbered image naming option

      Currently we're counting the files inside the images folder or reading
      database lenght to get the image name.
      We are not really checking for the next available number which could
      cause that we're loosing made images.

      • Example 1:
        We have 3 images: 0001.jpg, 0002.jpg and 0003.jpg
        Next image-name will be named 0004.jpg
        Everything is fine here

      • Example 2:
        We have 2 images: 0001.jpg and 0003.jpg
        Next image-name will be named 0003.jpg!
        This will override the already existing 0003.jpg!

      Since i have no quick solution, let's disable numbered image naming for now.

• Other changes:
  • collage:
    • add "Please wait" message on continuous collage
    • remove unneeded tmp picture
    • prettier original file naming (if we like to keep original images)
  • Logging:
    • rename "gphoto logs" to "camera log"
    • Show camera log independent of dev mode
    • log issues while post-processing inside the camera log
  • api:
    • Remove unneeded file-type checks all around the Photobooth api (we check for jpeg images already inside the api/applyEffects.php)
  • lib:
    • add central camera log function