Add customisable tooltips

[AlanRynne]

The current tooltip implementation displays all the data available for that object in the viewer, this has a couple of limitations:

• It will only properly display the first level of properties.
• Cannot be customised to show other data that is not contained in the object. i.e. mapping data from non-speckle sources to existing speckle objects.

Ideally, the tooltip should show only the fields that have been added to Object Data, which would fix both issues mentioned above

This requires compiling a map of TooltipData objects when new data is loaded, in a similar way we're currently keeping track of selectionIds.