node : add language detection support

[danbev]

This commit add support for language detection in the Whisper Node.js addon example.

The motivation for this is that currently there does not seem to be a way to get the language detected by whisper.

Examples usage:

$ node examples/addon.node/index.js --language='en' \
    --model='models/ggml-base.bin' \
    --fname_inp='samples/jfk.wav' \
    --detect_language=true
whisperParams = {
  language: 'en',
  model: 'models/ggml-base.bin',
  fname_inp: 'samples/jfk.wav',
  use_gpu: true,
  flash_attn: false,
  no_prints: true,
  comma_in_time: false,
  translate: true,
  no_timestamps: false,
  detect_language: true,
  audio_ctx: 0,
  max_len: 0,
  progress_callback: [Function: progress_callback]
}

{ language: 'en' }

And if the language option is set to "auto":

{
  language: 'en',
  transcription: [
    [
      '00:00:00.000',
      '00:00:07.600',
      ' And so my fellow Americans, ask not what your country can do for you,'
    ],
    [
      '00:00:07.600',
      '00:00:10.600',
      ' ask what you can do for your country.'
    ]
  ]
}

[zdm]

@ggerganov

Could you please merge this PR?
We tested it - it works without any problems.
It improves nodejs addon and make possible to retrieve detected language.