Add additional audio attack methods for enhanced evaluation

[hastagAB]

Introducing an additional set of audio attacks to enhance the capabilities of AudioSeal for evaluating the robustness of audio watermarking techniques.

The following effects have been added:

1. Pitch Shift: Changes the pitch of the audio without altering the speed, enabling evaluation under shifted tonal characteristics.
2. Reverse: Reverses the entire audio signal, simulating playback in reverse.
3. Clipping: Clips the audio signal at a specific threshold to simulate distortion due to high volume levels.
4. Time Stretch: Changes the duration of the audio without modifying the pitch, useful for testing stretched audio scenarios.
5. Tremolo: Applies amplitude modulation at a specified frequency, creating a tremolo effect.
6. Flanger: Introduces a delayed version of the signal with periodic modulation, creating a swirling effect.
7. Distortion: Amplifies and clips the audio signal, introducing harmonic distortion.
8. Bit Crusher: Reduces the bit depth of the audio signal, adding digital distortion for lo-fi quality simulation.
9. Vocoder: Modulates the audio signal with a carrier frequency, creating a robotic sound effect.
10. Ring Modulation: Multiplies the audio signal with a sine wave, resulting in a metallic sound effect.
11. Granulate: Breaks the audio into overlapping grains, creating a stutter-like granulated effect.

[antoine-tran]

Duplicate facebookresearch/audiocraft#507