Add: verbose mode to control console output level

[AlbertoCuadra]

Description

Currently, console output in the Combustion Toolbox is controlled through object-specific flags such as FLAG_RESULTS (used in solvers) or ad-hoc print statements in other modules (e.g., during database generation or data processing).
This leads to inconsistent behavior and limited flexibility when managing printed information across different components.

To improve consistency, a unified verbose property should be introduced at the class level across all objects that produce console output — including solvers, databases, and utility classes. This property will standardize how information is displayed and allow users to control verbosity in a modular, object-oriented way.

Proposed Implementation

• Introduce a verbose property in all relevant classes (e.g., solvers, database generators, utilities).
• Replace existing flags such as FLAG_RESULTS with the new verbose property.
• Define consistent verbosity levels across the toolbox, for example:
  • 0 – Silent (no console output)
  • 1 – Minimal output (key results only)
  • 2 – Standard output (default; includes progress and main results)
  • 3 – Detailed/debug output (intermediate steps, timings, or diagnostic info)
• Ensure internal print or disp calls are wrapped in conditional checks using the object’s verbosity level.
• Optionally, propagate verbosity settings to dependent objects (e.g., a solver calling sub-solvers or utilities).