clean up folder used as pseudo branches of voltha pipeline-scripts

* delete all folders used as pseudo branches for older voltha releases
  (including the unused playground) since those pipeline-scripts are now
  pulled in from the respective release branches for ci-management and
  are not needed in master anymore
* move all files from pseudo branch jjb/pipeline/voltha/master folder to
  jjb/pipeline/voltha folder to remove the mention of a branch in the
  script repo path
* remove 'master/' from path for all active pipeline scripts
* remove makefile used previously to copy folders as pseudo branches for
  releases

Signed-off-by: Jan Klare <jan.klare@bisdn.de>
Change-Id: Ib2f93ec021d0e12f70d550ccadd812c6408bf1ce
Signed-off-by: Jan Klare <jan.klare@bisdn.de>
diff --git a/jjb/voltha-e2e/master.yaml b/jjb/voltha-e2e/master.yaml
index 0710265..d29f779 100644
--- a/jjb/voltha-e2e/master.yaml
+++ b/jjb/voltha-e2e/master.yaml
@@ -85,7 +85,7 @@
           # 20230828 - while master branch did not (?)  Script does
           # 20230828 - show in the jenkins UI but w/o updates. 
           # ---------------------------------------------------------
-          pipeline-script: 'voltha/master/bbsim-tests.groovy'
+          pipeline-script: 'voltha/bbsim-tests.groovy'
           pipeline-branch: 'master'
           time-trigger: "H H/23 * * *"         # Build daily at 11pm
 #          time-trigger: "H/30 * * * *"        # Build every 30 min
@@ -154,7 +154,7 @@
       - 'voltha-periodic-test':
           name: 'periodic-voltha-dt-test-bbsim-master'
           build-node: 'ubuntu18.04-basebuild-4c-8g'
-          pipeline-script: 'voltha/master/bbsim-tests.groovy'
+          pipeline-script: 'voltha/bbsim-tests.groovy'
           pipeline-branch: 'master'
           code-branch: 'master'
           time-trigger: "@daily"