feat(browser-test): update docker image, args and lightpush endpoint behavior to match nwaku/10ksim

[adklempner]

Description

The REST API and cli args exposed by our browser-simulation image does not match with nwaku REST API/CLI args, specifically the lightpush endpoint is outdated. Other behavior, like bootstrapping (which in 10ksim is handled by the orchestration environment, not any of the fleets) needs to match expectations as well (e.g. instead of default bootstrapping, read ENRs from docker env and properly parse for setting bootstrap peers manually in createLightNode)

User Story

As a DST dev, I want to be able to use the js-waku Docker image and perform a lightpush with similar behavior and configuration as nwaku image

Proposed Solution / Feature Design

Optional: Diagram or Draft of Design

Notes

[adklempner]

assuming #2619 is done, estimate this takes ~4 hours

ensuring this works locally with nwaku adds ~2-4 hours and am not going to pursue initially; I prefer to deliver this to DST to try in 10ksim first and ensure lightpush endpoint behaves as expected in that environment