Export discrete_log from ntheory
Export discrete_log from ntheory

Refs -- sympy/sympy#11502

kaushik94/sympy,kaushik94/sympy,souravsingh/sympy,skidzo/sympy,madan96/sympy,yashsharan/sympy,souravsingh/sympy,souravsingh/sympy,chaffra/sympy,jaimahajan1997/sympy,yashsharan/sympy,jaimahajan1997/sympy,aktech/sympy,jaimahajan1997/sympy,aktech/sympy,madan96/sympy,kaushik94/sympy,chaffra/sympy,skidzo/sympy,madan96/sympy,aktech/sympy,skidzo/sympy,yashsharan/sympy,chaffra/sympy