Add support for directories and CSV output for cat command

[manojkarthick]

Directory support:

• Add supports for directories as a parameter to the cat command.
• When a directory is provided, the directory is traversed recursively and all the non-hidden, non-symlink files are displayed.

CSV support:

• Adds support for displaying Parquet files in CSV format
• CSV output format is not supported if the Parquet schema contains Struct or Byte fields.
• If one of the input files for the cat command does not support CSV format, an error message is displayed and skipped. The contents of the other files will still be displayed.

Version bump: Bumping the version of the package to v0.2.0