Remove auth-related nova-manage commands
Remove auth-related nova-manage commands

Drop support for management of deprecated auth by deleting
the following nova-manage commands:
* role *
* export *
* project/account * (except scrub and quota)
* shell export
* user *

Additionally, delete relevant documentation and tests.

Related to bp remove-deprecated-auth.

Change-Id: Iad9787f696cb55d4673d68fc60851c7f5bd25805

n0ano/ganttclient