Posiedon Code Removal

[harryswift01]

Posiedon is to be removed and replaced with imports from https://github.com/jkalayan/waterEntropy which handles the water entropy.

• Remove posiedon Directory
• Remove PoseidonHelper.py

This should also in turn resolve the variables defined but not referenced issues that were within posiedon as stated in issue #52