Use classic Java bindings / codegen stack in CN QS

The CN QS demonstrates the technology that is currently recommended. The decision was made to continue to use the classic Java tech stack (e.g., Java ledger bindings, Java template codegen, Java codegen classes) and the CN QS needs to migrate to use this. This involves all the steps from build, backend application, documentation updates, etc.

The Transcode Java technology can be kept as an Alpha feature but it cannot be the default.

Start by tracing the CN QS build and backend application configuration to identify where the current Transcode Java stack is selected. Check the Java ledger bindings, template codegen, and generated Java classes used by the quickstart. Done means the classic Java stack is the default across build, backend, and documentation, while Transcode Java remains available only as an Alpha feature.

Written by the indexing model from the issue text.