Use new data layer by default

[elevran]

What would you like to be added:
Enable the new extensible data layer instead of the current implementation.
Allow existing to run for a release as deprecated and the remove the code.

Why is this needed:
Transition to extensible data layer to provide more flexible data collection for EPP decisions and avoid duplicate fixes in both implementations.

[elevran]

/milestone Data Layer Foundational Implementation

[elevran]

work items

• validate performance and scale via benchmarking (incl. memory and goroutine)
• flip on/off by default
• ensure configuration is passed to data layer for setup
• create issue (and later PR) to remove existing backend/ package