Add plotting module back to Nodejs version

[risenW]

In order to support interactive plotting in the Nodejs Jupyter notebook, we need to add the plotting module and its types back to the danfojs-node lib. See discussion here.

[DonJayamanne]

@risenW DId you want me to submit a PR for this?

[risenW]

@risenW DId you want me to submit a PR for this?

@DonJayamanne if you have the time, please do.

[DonJayamanne]

Thanks, sorry I didn't get to this, been very busy with an upcoming relocation...

[risenW]

Thanks, sorry I didn't get to this, been very busy with an upcoming relocation...

@DonJayamanne No worries, I fixed this already, and pushed to the latest version v0.3.4