Add PLS-DA to Statistical Analysis

[XinsongDu]

Add PLS-DA (first check online what PLS-DA) to the pipeline. Sample data can be used to test your code. Steps:

• Google the term and learn about what PLS-DA is.
• Write code to create PLS-DA for Sample data.
• Analyze input and output of your code, add argument parser for Python or argument parser for R.
• Check code qualify using pylint (if using Python) or lintr (if using R) and improve code quality based on checking results.
• Modify main.nf to integrate your new code to RUMP and test your code.
• Make a pull request and wait for review.

Using MetaboAnalyst and their sample data to do PLS-DA and observe what the results look like might be helpful.