Misc edits: makefiles/ and jjb templates.

Makefile
config.mk
makefiles/consts.mk
makefiles/lint/jjb.mk
---------------------
  o config.mk - initial setup to support library and local makefiles.
  o Move jjb lint target (~test) into jjb.mk, conditional logging verbosity.

makefiles/git-submodules.mk
---------------------------
  o Restore skeleton git submodule dir(s) after 'make sterile' is used.
  o Some external repo content placed under revision control.
  o Odd state: make clean induces bogus git status 'deleted:'

jjb/api-test.yaml
-----------------
  o Lint cleanup, fixed a complaint about replacment of non-expansive !include token.

jjb/defaults.yaml
-----------------
  o jjb + LinuxFoundation submodules have gone stale.
  o note download sources for a pending upgrade.

jenkins_jobs.errors.JenkinsJobsException:
  Failed to find suitable template named '{project-name}-ci-jobs'
-----------------------------------------------------------------
  o Finding 2020 changeset(s) also fail linting with this problem.
  o Might have an intermittent failure to debug in here.
  o Several jobs have run cleanly in the interim.

Change-Id: I20a0f3f0f731d6f312e5798af6049afd2e18c1c9
diff --git a/jjb/defaults.yaml b/jjb/defaults.yaml
index 38cfa54..6d4f97b 100644
--- a/jjb/defaults.yaml
+++ b/jjb/defaults.yaml
@@ -8,6 +8,8 @@
     # disabled: '{disable-job}'
     disable-job: false
 
+    # https://docs.releng.linuxfoundation.org/projects/lftools/en/latest/commands/version.html
+    # https://docs.releng.linuxfoundation.org/projects/lftools/en/latest/release-notes.html#v0-35-11-4
     # lftools
     lftools-version: '~=0.26.2'