Improve capabilities status reporting

What
Currently when user creates capabilities CR and there's an issue with any of the CRUD operations that the CR triggers, the status of the CR is not updated. This means that a user will not know what went wrong unless looking at the operator logs.

While this is acceptable, it's not always possible for the user to access 3scale logs, for example, with 3scale operator running in cluster scoped mode and dev users have only access to their particular namespace it might be impossible to debug without admin intervention.

To prevent this all capabilities CR should be having the status updated in any situation, success, in progress or failure.

How
We have decided to re-use the existing fields for communicating the state of the resource with user:
https://github.com/3scale/3scale-operator/blob/master/pkg/common/status_conditions.go#L57

Note: Tenant does not use this status, we need to include it, rest of capabilities seems to be using it.

The general idea is to use:

    Reason ConditionReason - success/in progress/error

    Message string  - if err, the message field should describe the reason for the error