Added volume conversions (#5607)

* Added volume conversions

This is a file which has relevant function which helps in conversion between volume units.
Available Units:- Cubic metre,Litre,KiloLitre,Gallon,Cubic yard,Cubic foot,cup

The file is also written in a way that , adding a new unit can easily be done by modifying tuple available in the source code

* Formatted file

The file was formatted to follow the syntax formatting rules of the repo

* Formatted file further