[Enhancement] Add the ability to filter point context layers created based on Related Table

[janbur]

This is child of: #141

Objective

Once we enable adding Related Table as a point context layer, it would be helpful to allow filtering the data (points), based on existing attributes.

Solution

This could be implemented similarly to slicers for Related Table indicator layers:

As a result, a user of the dashboard will be able to filter context layers, e.g. show only points of Category A, or B:
som_sample_related_table_with_points.xlsx

This could be integrated into Related Table Context Layer global configuration, which can be overwritten within the context of the project (see the img below on how to override the default style of the context layer within a given project)::

Step 1 - go to list of context layers within a project and click Config (3)

Step 2 - check to override default (global) styles, labels etc