[libc][math] Implement double precision exp10 function correctly rounded for all rounding modes.

Implement double precision exp10 function correctly rounded for all
rounding modes.  Using the same algorithm as double precision exp
(https://reviews.llvm.org/D158551) and exp2 (https://reviews.llvm.org/D158812)
functions.

Reviewed By: zimmermann6

Differential Revision: https://reviews.llvm.org/D159143