webos_enhanced_submissions, webos_submissions: Switch to use WEBOS_VERSION

:Release Notes:
* Modify webos_enhanced_submissions.bbclass and
  webos_submissions.bbclass for the "Decentralized BOM", where the
  unconventional PREFERRED_VERSION settings in
  webos-preferred-versions.inc are moved into the individual
  component recipes as a WEBOS_VERSION assignment.
* The definition of "enhanced submission" is changed to be that the
  submission portion of WEBOS_VERSION has "_<40-char-revision-hash>"
  appended to the submission number and the definition of a basic
  submission is changed to be that it doesn't have it appended to the
  submission number. WEBOS_GIT_PARAM_TAG is set by
  webos_enhanced_submissions; it should no longer be set by recipes.
* A consequence of this is that the recipes for all webOS components
  that are housed in Git repos will be required to inherit from
  webos_enhanced_submissions and only those that do not will be able to
  inherit from webos_submissions.

:Detailed Notes:
* webos_enhanced_submissions splits WEBOS_VERSION into
  WEBOS_COMPONENT_VERSION, WEBOS_SUBMISSION, WEBOS_GIT_PARAM_TAG,
  WEBOS_GIT_REPO_TAG, WEBOS_SRCREV, SRCREV, and PV. Recipes must
  override WEBOS_GIT_REPO_TAG if their components' tag names do not
  follow the webOS standard 'submissions/<N>' scheme.
* webos_submissions splits WEBOS_VERSION into WEBOS_COMPONENT_VERSION,
  WEBOS_SUBMISSION, and PV.
* The original definition of "enhanced submission" where _<PR> could
  optionally appear after the submission to select a different revision
  of the recipe never worked correctly because of a bug in bitbake, and
  now that the use "PR Service" has become the default, it no longer
  makes sense to offer this functionality.

:Testing Performed:
Builds the image from the same source even when tag is accidentally
moved to different revision.

:QA Notes:
No change in image.

:Issues Addressed:
[GF-5328]  Improve build performance and allow to build completely from
           PREMIRROR
[GF-12492] Convert from setting PREFERRED_VERSION centrally to setting
           WEBOS_VERSION in each recipe
[GF-35136] CCC: Decentralized BOM

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I142f669deb4bbf6c53c0346b76bba4e43f19b2f6
Reviewed-on: https://g2g.palm.com/1995
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>