create callbacks/Readme.md

[drelliche]

From the code review main...joy-code-review

Callbacks

Callbacks are what provide interactivity with the app. When users click on interactive elements like buttons, nodes, drop-down menus, etc., callbacks are triggered. Callbacks take inputs (what was interacted with that is triggering a new action) and outputs (what will next change in our layout).

It is helpful to document what happens when a user interacts with the app... what callbacks are triggered and under what circumstances?

E.g. (and I'm probably wrong):

• active_node_in.py is triggered when a user clicks on a node in the displayed graph which represents an asset or a button that is displaying the name of an asset. The input could be ... or ..., and the outputs...

• add each callback here, consider adding screenshots even of the elements that are inputs and/or outputs.

[drelliche]

First created here: 18c924e

When the network_analysis branch gets merged into main, I will close this issue.