Add Support for SDF File Format in NGL Plugin

[wverastegui]

Problem:
Visualizing molecule structures directly from SDF format in NGL viewer would enhance convenience.

Specific Use Cases:
The QCXMS tool, used for mass spectrometry prediction, processes SDF files to generate conformers. Directly visualizing from SDF files would simplify the workflow, particularly when dealing with multiple molecules.

Alternatives:
Though converters exist to convert SDF files to PDB format, integrating direct SDF support in NGL plugin would avoid unnecessary conversions.