NWBExplorer issues on v2

[pgleeson]

• [x] When a new workspace is created from a repo with many nwb files, the ws opens showing the main "Welcome to NWB Explorer" screen (with external links to standard examples...). Better to load any one of the nwb files in the resources.
• [ ] Colours of traces persist between loading of nwb files, e.g. load one Ferguson dataset, plot everything (list of datatypes all get assigned random colour), load another nwb file by clicking on the resource, all the colours are preassigned from previous load...

Formatting on Python console: (<- moved to #526 )

[pgleeson]

Note: formatting of latest developemnt NWBE is fine/more readable, so this is getting overwritten elsewhere in OSBv2: