Implement `sqrt` with higher precision

[Alexangelj]

The solmate sqrt is good for inputs in WAD 1E18 units. The output value has precision of 1E9.

We need a sqrt that can take an input in at least 1E27 units and output higher precision than 1E9.

[Alexangelj]

The sqrt limits the precision in the case exp(-2) < x < 1 - exp(2) of the Ndtri.ndtri(x) funciton.