--add GenericDialog class in order to provide
same implementation for all settings::dialogs.
As a first step GenericDialog provides a common
showInlineMessage api
--we introduce handlers that are going to be
responsible for the ui parts of settings windows.
So having data structures, MVC for models/tables that
are used and Handlers for any ui interaction
simplify the implementation and make it more
structured in order to be maintained and grow
safely.