BFT docs: add SmartBFT documentation to the ordering service doc

### Current Status

The `docs/source/orderer/ordering_service.md` doc is missing info about Smart BFT

### Expected

The `docs/source/orderer/ordering_service.md` doc should have info about Smart BFT
In addition, one should add Smart BFT metrics to the `docs/source/metrics_reference.rst` doc.

### Solution

_No response_

### Please let us know if you plan to work on this.

Maybe.