MF related update 3 (#3)

* Refine rating computation with rounding and clipping
- Adjust rating calculation to round and clip values.


* Update example notebook of MF
- Added notation related to linear constraints
- Updated the output results under the new data simulation method (round to 0.5)



* Revise ReHLine MF tutorial for a user-friendly manner
- Updated the tutorial to clarify the useage of plqMF_Ridge. 
- Improved the mathematical formulation. Added linear constraint to the overall objective function
- Enhance ReHLine MF tutorial with installation steps


* Fixed notion errors in API of plqMF_Ridge

Author: DataboyUsen