benchmarks: cleanup footprint tests (nano kernel)

Remove float option from 'max' configuration and add a new
'float' test for hardware that supports floating point.

Move configuration files into directories to ease maintenance.

Change-Id: Ibf4c88ea946a78b8025bc61409b0ab661250f4fb
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
12 files changed