CHORE: implement utility code for generating list of relevant warning diagnostics based on arguments

[reactive-firewall]

Context: As identified in review of PR #346 additional diagnostics should be implemented to ensure user migration to the v6+ series. Version v6.0 specifically will introduce new behavior without fully replacing legacy behavior, thus users should be made aware that the change is coming.

Goal: implement a function to generate a list of warnings based on the invoked arguments:

E.g., consider:

def emit_deprecation_warnings(args: CustomNamespace) -> list[str]:
    """Return list of deprecation warning messages."""
    warnings_list = []
    
    if args.with_license_file and not args.with_license_files:
        warnings_list.append(
            f"DEPRECATION WARNING (v6.0):\n"
            f"  --with-license-file is deprecated.\n"
            f"  Use --with-license-files instead.\n"
            f"  See: {__repo_url__}/issues/242"
        )
    
    return warnings_list

This allows for integration via the exsisting: create_warn_string function, E.g.:

def create_warn_string(args: CustomNamespace) -> str:
    warn_messages = emit_deprecation_warnings(args)  # NEW
    warn = partial(output_colored, "33")
    
    # ... existing warning logic ...

[reactive-firewall]

Also consider:

def emit_deprecation_warnings(args: CustomNamespace) -> list[str]:
    """Return list of deprecation warning messages."""
    warnings_list = []
    
    if args.with_notice_file and not (args.with_notice_files or args.with_other_files):
        warnings_list.append(
            f"DEPRECATION WARNING (v6.0):\n"
            f"  --with-notice-file is deprecated and may be removed in the future.\n"
            f"  Use --with-notice-files instead.\n"
            f"  See: {__repo_url__}/issues/242"
        )

    return warnings_list