prepare-submission.sh: Add simple script for creating webos tags

:Release Notes:
Creating submission or version tags is a bit error prone, most common
issues are:
* tags are moved after they have been used in build
* tags aren't annotated, so we cannot find who created or moved tag
* tags don't match expected format or minimal submission (1),
  version (0.1.0)
* developers are tagging latest commit in their local tree (after they
  check that it was merged on gerrit), but even when it's the same
  commit it has different revision in master branch, because it was
  cherry-picked by gerrit.

:Detailed Notes:
This script checks for issues listed above, creates correct tags,
pushes tags and allows automatic update of WEBOS_VERSION in recipe
when -r parameter is used. It will also show how commit subject and
git log --oneline in ":Detailed Notes:" should look.

:Testing Performed:
Created couple of tags with every possible combination of used
parameters on normal clone as well as on bare clone, bare+mirror
clone cannot be used -> script detects that and shows error.

:QA Notes:
No change in image

:Issues Addressed:
[GF-5328]  Improve build performance and allow to build completely
           from PREMIRROR
[GF-12492] Convert PREFERRED_VERSION to WEBOS_VERSION and modify
           webos_enhanced_submissions.bbclass

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I9fe5d66c1e5cbb5e10628af6dd61d1b6c15d660d