New Templates L&F

Contains the work required for #116. This is currently incomplete and in a first draft state.

I'll continue to deliver changes to this branch until I'm happy with the results.

Taking advantage of the new checklist functionality, here's a breakdown of the work involved and the current progress;

- [x] Templates are to be displayed in a table
- [x] Templates can be searched
- [x] Number of templates displayed can be filtered (i.e. pagination)
- [x] Templates can be dragged and dropped to change their order
- [x] Templates are to be modified using a wizard dialog
- [x] Multiple templates can be selected and deleted
- [x] Multiple templates can be selected and exported
- [x] Templates can be imported
- [x] Obsolete code/content is removed
- [x] Legacy code is improved to be more efficient