Python part of Manilaclient does support auth by token, but
CLI part does not. Therefore, add two new optional args
with related env vars:
--os-token [OS_TOKEN]
--bypass-url [MANILACLIENT_BYPASS_URL]
Also, disable checks for other auth data if these two are provided.
Change-Id: I567294dfb61e702410c3f0fadc15a04667075434
Closes-Bug: #1572095