Service token support [xena]

[coreycb]

• Add configuration for use of service tokens

Add a new template to configure the service_user ini file section and also add two needed parameters in keystone_authtoken configuration

(cherry picked from commit f8c8861b4f0cb2181792013f9a973b3924a1e831)

• Fixes for service tokens

• Make admin role configurable

• Move keystone_authtoken configuration from mitaka version to base version

• Sync service_user config with keystone_authtoken for the base version

(cherry picked from commit 7bcb1942ad11aafa307d5872d7b36a7bd7908288)

Conflicts Resolved: charmhelpers/contrib/openstack/context.py

• Fix tests

(cherry picked from commit 4090532d1194d215cf5b065c1c108072652b8cfe)

• Add test for this feature

(cherry picked from commit e43008d7671433e44e27c58312292d8fb504fc59)

• Fix test

(cherry picked from commit c7cc5db9e4acd4dd66282bd4303f59db9ef8e9c6)

• Add service token parameters to last authtoken template

Copy parameters added in pull request #740 to the newest keystone-authtoken template.

(cherry picked from commit 23d838bc55c842ea27ba29f4b1097b2ec9469fca)

• Pin tox<4.0

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Co-authored-by: Jorge Merlino jorge.merlino@canonical.com (cherry picked from commit 32772ff502e179027f46daaa04729a2f5d49f5e5)