Give a way to save why a service has been disabled

Port from nova https://review.openstack.org/#/c/26020/

We added a field to the table of service to log a reason when a
service has been disabled.

We added a new API extension called os-extended-services.

The new extension will extend the os-services extension adding a
method for disabling a service and specify a reason for that:
PUT /v2/{tenant_id}/os-services/disable-log-reason

When the os-extended-extension is loaded the call:
GET /V2/{tenant_id}/os-services
will return the list of services with disable reason information
if that exists.

DocImpact

Change-Id: I885e43132b0e49b63f7858abd3fcffe1b78d3fd8
Implements bp record-reason-for-disabling-service
Merge "Give a way to save why a service has been disabled"