Fine-grain Plotting of Feature Values

[serwarde]

Is your feature request related to a problem? Please describe.
The current implementation (see #51) of the two layer bar chart aggregates all values for all features within a selected layer. We want to break down to the values of each feature separately.

Describe the solution you'd like
After selecting a layer, if multiple features are available, the user selects one, and that plots all values for that given feature.

Describe alternatives you've considered
N/A

Additional context
N/A