Improve target coverage for the reuse license checker.

misc
----
  o Copyright notice update from onf v1 to onf v1.1

makefiles/etc/utils.mk
----------------------
  o Function path-by-makefilepath-by-makefile():
    - Replace $(subst include.mk) with $(dir) so path construction becomes generic.
    - Added wrapper function genpath-makefiles() to improve call usability.

makefiles/lint/license/include.mk
makefiles/lint/license/reuse.mk
makefiles/lint/license/install.mk
---------------------------------
  o Added requirements.txt for reuse tool install (ability to vesion and freeze for release).
  o Define command var REUSE= so local devs can override.
  o Added banner-{enter,leave} for logfile visibility.

makefiles/lint/license/include.mk

makefiles/lint/license/help.mk
------------------------------
  o Document a few missing targets for 'make help' and 'make lint-reuse-help'.

[HOWTO: test]
-------------
% make sterile
% make venv                 # install virtualenv
% make lint-reuse-install

% make sterile
% make lint-reuse-version

% make sterile
% make lint-reuse

Change-Id: I91f4789981f3d3c5bc744d2db99374f9790e3b98
diff --git a/makefiles/lint/license/help.mk b/makefiles/lint/license/help.mk
index ffd98bd..02ae791 100644
--- a/makefiles/lint/license/help.mk
+++ b/makefiles/lint/license/help.mk
@@ -42,6 +42,8 @@
 	  'License check locally modified files (git status)'
 	@printf '  %-30s %s\n' 'lint-reuse-src'\
 	  'License check files by path'
+	@printf '  %-30s %s\n' 'lint-reuse-install'\
+	  'pip install --requirements ./conf reuse'
 
 $(if $(DEBUG),$(warning LEAVE))