Token passthrough for nailgun client in ostf

- Ostf config generator makes api requests to nailgun
- Changed requirements of pecan to version that used in production (0.4.5)

related to blueprint access-control-master-node
Related-Bug: #1339082
Change-Id: I96861ef75adbb813a9c91a88e1db16211dac9c4c
Merge "Token passthrough for nailgun client in ostf"