Add golang makefile library targets for 'go mod'

makefiles/include.mk
makefiles/golang/include.mk
makefiles/golang/mod-update.mk
------------------------------
  o Added target mod-tidy   to invoke 'go mod tidy'   w/output banner.
  o Added target mod-vendor to invoke 'go mod vendor' w/output banner.
  o Added helper target mod-update to invoke mod-tidy and mod-vendor.
  o Targets help-summary (~help) and mod-update-help document use.
  o Dev mode flag LOCAL_FIX_PERMS=1 can be added to correct problems
    when docker mount is unaware of user uid/gid.

makefiles/targets/sterile.mk
----------------------------
  o Corrected a comment typo.
    + Amusing when this checkin message also requires a "correction".

Change-Id: Ia50c43a7b7bab4340a5390956cccd857a938c8c9
diff --git a/makefiles/include.mk b/makefiles/include.mk
index fcb57fd..1bea64e 100644
--- a/makefiles/include.mk
+++ b/makefiles/include.mk
@@ -71,7 +71,8 @@
 ##------------------------------------##
 ##---]  Languages & Interpreters  [---##
 ##------------------------------------##
-# include $(ONF_MAKEDIR)/src/golang/mod-update.mk
+# [TODO] $(if $(golang-mode),$(eval include))
+include $(ONF_MAKEDIR)/golang/include.mk
 
 ##---------------------##
 ##---]  ON_DEMAND  [---##