Event graph view

Features:
- [x] Generate a graph view for events in the current file
- [x] Generate a graph view for events referenced (or referenced by) events in the current file
- [x] Draw edges from events to events they trigger
- [ ] Display the event id and event comment above each event
- [x] On clicking an event, go to it in code
- [x] On hovering over an event, show all used/set scopes
- [x] On pressing a button, export the graph to an image
- [x] On pressing a button, export the graph to json
- [x] Generate a graph view for the given saved json

Proposed graph return structure
```f#
type GraphDataItem =
{
id : string
displayName : string option
documentation : string option
references : string list
location : range option
details : Map option
}
```