Give a way to save why a service has been disabled.

Implements blueprint record-reason-for-disabling-service

We added a field to the service table 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 reason information it that exists.

DocImpact
Change-Id: I87a4affc45160796ff11c7b03e591e6aba73d62a
Merge "Give a way to save why a service has been disabled."