Check health of database replicas

[clintonb]

Is there an existing issue that is already proposing this?

• [x] I have searched the existing issues

Is your feature request related to a problem? Please describe it

My application uses a read replica to help reduce load on the primary. TypeORM health checks work out-of-the-box for the primary, but need extra configuration to work with the replica.

Describe the solution you'd like

I want Terminus to either check the replicas or give me the option to configure checks for the replicas.

Teachability, documentation, adoption, migration strategy

TBD

What is the motivation / use case for changing the behavior?

Ensure all dependencies are monitored as part of health checks.