Issue 5852 = Remove turbo mode from the code base

Description: Turbo mode is a feature that improves the search performance
for a low number of highly active connections. Since its introduction the
deployment model has changed and this feature is no longer required. Turbo
mode adds some complexity to the code so removal will simplify connection code.

Fix description: Following investigation into the pros/cons of turbo mode it has
been decided that this feature should be removed from the codebase.

Relates: #5852

Reviewed by: ?