Allow 'Tools' to expose preference options

[lmihalkovic]

The current preference dialog is hard wired to display 2 tabs (settings/network), with fixed contents. Issues like #4180 show that there is the use case for extending this scheme.

A possible way would be to have a list on the left-hand side, with each page displayed on the right-hand side. Following this pattern (rather than adding more tabs) would allow easier runtime extension of the list.

Compatibility with existing tools would be preserved with the creation of a Tools2 interface or a separate ToolsExt. Either way, this would expose a PreferenceDialogPanel getToolPreferencesPanel() method.

[lmihalkovic]

Due to lack of interest