Add more owners of API directory

This dir is home of the modularized SDK now. Add hansson and
modularization team as explicit owners so that we can e.g. approve new
modules being added.

Bug: 184125529
Test: No
Change-Id: I97802b98d24309759f9cf5d3192da6b80dc7657b
Merged-In: I97802b98d24309759f9cf5d3192da6b80dc7657b