Add section in guide describing dblink output

[ngmarchant]

Describe the format of the linkage structure samples, diagnostics, and point estimates.

[YathishK]

What is the application we need to use to open driver-state file created in output folder ?

[ngmarchant]

What is the application we need to use to open driver-state file created in output folder ?

The driver-state file is a serialized Java object. Together with partitions-state.parquet, it encodes the state of all variables in the model so that sampling can be resumed. It's not intended to be read by an external application.