Robust image I/O

[ssheorey]

• Use file signatures (beginning bytes) instead of filename extension (png/jpg) to select decoder. jpg files with png extension and vice versa are read correctly.
• Catch libjpeg errors and report as normal Open3D exceptions. Change Open3D warnings to errors (exceptions) on jpeg I/O error.

Output if a corrupt file is given to jpeglib:

>>> im=o3d.io.read_image("texture1_corrupt.jpg") 
Corrupt JPEG data: 67 extraneous bytes before marker 0xc0
[Open3D WARNING] libjpeg error: Quantization table 0x01 was not defined
>>> im=o3d.t.io.read_image("texture1_corrupt.jpg") 
Corrupt JPEG data: 67 extraneous bytes before marker 0xc0
[Open3D WARNING] libjpeg error: Quantization table 0x01 was not defined

Earlier, this used to crash the program (python or user C++ app, or Open3D viewer app) since libjpeg would immediately exit() with this error message.

Breaking change: Image read errors now Clear() the image to ensure an older image cannot be used in error. This is in addition to a WARNING message and returning false. We do not throw exceptions for Image IO, to be consistent with OpenCV.

References:

• OpenCV image IO
• libjpeg example.c

Type

• Bug fix (non-breaking change which fixes an issue): Fixes Error loading ShapeNet meshes with texture #4362
• New feature (non-breaking change which adds functionality). Resolves #
• Breaking change (fix or feature that would cause existing functionality to not work as expected) Resolves #

Motivation and Context

Checklist:

• I have run python util/check_style.py --apply to apply Open3D code style
  to my code.
• This PR changes Open3D behavior or adds new functionality.
  • Both C++ (Doxygen) and Python (Sphinx / Google style) documentation is
    updated accordingly.
  • I have added or updated C++ and / or Python unit tests OR included test
    results (e.g. screenshots or numbers) here.
• I will follow up and update the code if CI fails.
• For fork PRs, I have selected Allow edits from maintainers.

Description

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.