Function: rnfisnorminit
Section: number_fields
C-Name: rnfisnorminit
Prototype: GGD2,L,
Help: rnfisnorminit(pol,polrel,{flag=2}): let K be defined by a root of pol,
 L/K the extension defined by polrel. Compute technical data needed by
 rnfisnorm to solve norm equations Nx = a, for x in L, and a in K. If flag=0,
 do not care whether L/K is Galois or not; if flag = 1, assume L/K is Galois;
 if flag = 2, determine whether L/K is Galois

