Qt: Add initial Lua support.

Qt: Add initial Lua support.

Add a FunnelStatistics class, which is the main interface between the Qt
UI and the Funnel API.

Add FunnelTextDialog, which implements the text_window, ProgDlg, menu,
and other routines. Add FunnelStringDialog, which implements dlg_new.

We currently only support "Tools" menu items (MENU_TOOLS_UNSORTED, aka
REGISTER_TOOLS_GROUP_UNSORTED). Add a disabled placeholder to the
"Tools" menu in case we don't load any scripts.

Use "struct progdlg" instead of needlessly casting to
funnel_progress_window_t.

To do:
- Add support for MENU_STAT_UNSORTED, MENU_STAT_GENERIC, etc.
- Make the firewall config generator a Lua script?
- Add FunnelGraphDialog? It seems like it would be useful to
  make QCustomPlot accessible to Lua scripts.

Ping-Bug: 9845
Change-Id: Iefff02e9032ed1853666f7902509ed08b431e7a7
Reviewed-on: https://code.wireshark.org/review/9523
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>