Continuation of the general effort to convert gui pages to use OOP principles.
There are two visual alterations:
- Scrollbars have been enabled on the textboxes (only appearing when necessary).
- The "Special Technologies"/"Special Structures" subsection has been split in two (separation of concerns).
Note: This revision is a step towards adapting the civinfo page to load information from entity/technology/aura data files - where relevant - instead of from the {civ}.json files. (This is why the civinfo codebase has been relocated into the gui/reference folder.)
Requires D2734