Decouple TangoDB deployment from application level roll out

The current deployment of the TangoDB and DatabaseDS is coupled in a way that best supports development and initial testing efforts, however this is not fit for purpose in a production environment where the DB/DS is a long-lived service that has a lifecycle decoupled from the rest of the control system.

In order to move towards a component based and highly available system, it is necessary to decouple the TangoDB and DatabaseDS deployments from each other and the rest of the system so that they can be independently managed and an appropriate HA solution can be implemented for the DB (MariaDB).

• The TangoDB can still be deployed from the existing development helm charts
• The TangoDB can be deployed via the bitnami helm charts in an HA configuration
• The DatabaseDS can still be deployed from the existing development helm charts
• The DatabaseDS can be deployed independently and the existing DeviceServer deployments can be passed an explicit TANG_HOST value so that they are independent also.

Outcomes:

• The TangoDB can still be deployed from the existing development helm charts
• The TangoDB can be deployed via the bitnami helm charts in an HA configuration
• The DatabaseDS can still be deployed from the existing development helm charts
• The DatabaseDS can be deployed independently and the existing DeviceServer deployments can be passed an explicit TANG_HOST value so that they are independent also.