tools: power: pm-graph: Package makefile and man pages

BootGraph and SleepGraph man pages
- includes full descriptions of tool arguments and commands
- includes examples of common use cases

Makefile
- no build required, used only for install
- installs man pages and tools as libraries with links
- includes an uninstall

Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>