ci: remove dead bosh-release resource_type and teardown-director task

The bosh-release resource_type (dpb587/bosh-release-resource) is not
referenced by any resource, and teardown-director.{yml,sh} is not
referenced by the pipeline. Remove them.

Co-authored-by: Saumya Dudeja <saumya.dudeja@sap.com>

Author: neddp

ci/pipeline.yml

@@ -364,13 +364,6 @@ resource_types:
     repository: ljfranklin/terraform-resource
     username: ((dockerhub_username))
     password: ((dockerhub_password))
-- name: bosh-release
-  type: registry-image
-  check_every: 168h
-  source:
-    repository: dpb587/bosh-release-resource
-    username: ((dockerhub_username))
-    password: ((dockerhub_password))
 - name: gcs
   type: registry-image
   check_every: 168h