Add examples of different file types in Docs page

[appukuttan-shailesh]

Since NeoViewer makes use of Neo under the hood, it is expected to work with a variety of file formats.
It would be useful to demonstrate this with sample files on the documentation page.

This will help users easily identify the file formats that can be used and also test it out online.
For "generic" file formats, e.g. CSV, TXT etc.... we could demonstrate what is the necessary associated info that has to be made available for NeoViewer to work on these files.