Mezzanine release v2 script updates and metadata

[nicholas-fr]

Changes made over the past few months, used to generate mezzanine release v2, including:

• Annotations now added to green start frame and red end frame, starting from frame 1 (not frame 0).
• Stream duration is now exactly 60 seconds (instead of 60 seconds + 2 frames previously).
• Black background added behind QR codes to help with detection.
• Bit pattern added to the top left of the video (with frame number, total frames, frame rate, horizontal resolution and vertical resolution).
• Mezzanine audio sample rate now always 48kHz.
• A/V sync metadata is saved to JSON files named as follows: _avsync.json
• Metadata for each mezzanine stream, including video properties and license, now saved to JSON files named as follows: .json
• Mezzanine stream metadata for mezzanine release v2.
• Grouped assets and updated JSON configuration files (rjf) for generating mezzanine content into separate folders.

As part of the clean-up, I propose to remove the unused legacy scripts as well.

Together with the mezzanine release v2, this resolves issues #40, #38, #36, #29, #28, #18 and #20.

[rbouqueau]

I've regenerated the test content with the mezzanine v2.