[scripts][fuzzing] Make SSH options more flexible

This CL moves the SSH configuration from Host to Device
and makes it more flexible to handle arbitrary options.  This allows
other environments like ClusterFuzz to specify the options they need.

Bugs: SEC-107
Test: for f in scripts/fuzzing/test/*_test.py; do python $f; done
Change-Id: I5c7c35e5238e390f9cd4eb848a14d995e3271af8