Remove the SimpleEvent class and the caches from HistoricalEventManager

Changes:
- Delete SimpleEvent class
- EventTableModel converted to use HistoricalEvent
- Model also uses a generic approach to blocking categories & events instead of if statements in the logic
- EventFilter is generic based on the avaialble EventTypes
- HistoricalEventManager adds a synchronised region when events are being added
- Reintroduced a cap on the number of transient events held; set to 50.

Part of #827

Create a new Entity interface that represents the top levle objects that the simulation controls.
This entity is used to centralise the opening of the appropriate UI Window to show the details of
the entity. This oculd be a Mission or Unit Window.
The objective is to remove the coupling between the various UI Windows.

Changes:
- Create Entity interface and implement is Unit, Mission & Transportable
- MainDesktopPane replaces the openUnitWindow with a generic showDetails method
- The new showDetails method acts as a factory to select the appropriate UI window to display the selection.
- Update all calls to the old openUnitWindow with the replacement
- Update direct calls to the MissionWindow with the generic Desktop method
- Move the open details window logic into the MonitorWindow class

Part of #827

Changes:
- HistoricalEvent uses a Coordinates class for the coordinate column
- HistoricalEvent uses a Unit for the container property
- Add a cut down constructor where some properties are derived from the container
- EventTableModel will locate the best Entity instance from an event
- Update the constructors of the HistoricalEvent subclasses
- Event tab in Monitor window enables the Details button
- Event console command seperates out the coordinates and locations

Part of #827

Part of #827

Changes:
- ScientificStudy implements Entity interface
- DesktopPane showDetails method now supports ScientificStudy to display the details

Part of #827