Chinese Remainder Theorem | Diophantine Equation | Modular Division (#1248)

* Update .gitignore to remove __pycache__/

* added chinese_remainder_theorem

* Added Diophantine_equation algorithm

* Update Diophantine eqn & chinese remainder theorem

* Update Diophantine eqn & chinese remainder theorem

* added efficient modular division algorithm

* added GCD function

* update chinese_remainder_theorem | dipohantine eqn | modular_division

* update chinese_remainder_theorem | dipohantine eqn | modular_division

* added a new directory named blockchain & a files from data_structures/hashing/number_theory

* added a new directory named blockchain & a files from data_structures/hashing/number_theory