Windows: Add command line switch (/m noattach) that is equivalent to UI option "Only create virtual device without mounting on selected drive letter"

src/Mount/Mount.c

@@ -9135,6 +9135,10 @@ void ExtractCommandLine (HWND hwndDlg, wchar_t *lpszCommandLine)
 							// get the label
 							StringCbCopyW (mountOptions.Label, sizeof (mountOptions.Label), &szTmp[6]);
 						}
+						else if (!_wcsicmp (szTmp, L"noattach"))
+						{
+							mountOptions.DisableMountManager = TRUE;
+						}
 						else
 							AbortProcess ("COMMAND_LINE_ERROR");