[FEATURE REQUEST] default format options

[the-liquid-metal]

Currently, yt-dlp-gui selects the first item in video/audio option. Since item in those options can be a dozens, and user tend to download a particular format, it would be practical if there are default format options. Current video/audio option consist of compound spec: resolution, FPS, codec, etc. For default format purpose, these options should be break down into its component and placed in dadicated option: resolution option, FPS options, codec options, etc.

• resolution option. Consist of items: "greatest", [popular-resolution], "smallest"
• FPS option. Consist of items: "greatest", [popular-FPS], "smallest".
• codec option. Consist of items: [popular-codec]
• etc.

Since there is no certainty about the availability of the default format, yt-dlp-gui should provide a relaxed companion options.

• relaxed resolution option. Consist of items: "closest greater" and "closest lesser".
  If user select "1280x720" and "closest greater", but it is not available, then yt-dlp-gui should select "1980x1080" or any greater one but closest.
• relaxed FPS options. Consist of items: "closest greater" and "closest lesser".
  If user select "30" and "closest lesser", but it is not available, then yt-dlp-gui should select "24" or any lesser but closest.
• relaxed codec option. Consist of items: [popular-codec].
  If user select "H.264" and relaxed "AV1", but "H.264" is not available, then yt-dlp-gui should select "AV1" before any other options.
• etc.

Note:

• All default format options and its relaxed companions should be placed in "Advance" or "Options" tab (whatever you feel is right).
• For FPS case, items which contains fraction number are rounded to ceil value. That means, If user select "30" and "closest greater", but it is not available, then yt-dlp-gui should select "29.xx" before any greater one but closest.