doc: move tool guides in their own subdirectory

doc: move tool guides in their own subdirectory

This is to clarify the scope of these documents that are more tools than
sample applications.
Also this is a preparation step to add more tools and generate man pages
off of their rst files.

Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Acked-by: Luca Boccassi <lboccass@brocade.com>
Acked-by: John McNamara <john.mcnamara@intel.com>