Add Frontend features to Synthetic Monitoring using k6 API - multi-http, browser & scripted checks

[CatPerry]

What would you like to be added: There are a few pieces of functionality that a significant number of customers are requesting:

• Adding Multi-Http SM checks
• Running a script for your SM check
• In-browser checks that indicate success metrics of a website

Coincidentally and thankfully, all of this functionality has one thing in common: It all comes with the k6 api. So this year, the Synthetic Monitoring team will build a series of SM interfaces that use this powerful k6 api, under the hood.

Why is this needed: Key stakeholders are asking for this functionality, and we have a small team in place that can execute this

Additional context The SM team has been conversing in detail with the K6 team and finance during this process

*GENERAL PHASING OF THESE 3 FEATURES: Phase 0: Multi-http

• [x] Modify current UI/logic to add multi-http - DONE by Cat
• [ ] Create a dashboard that works for multi-http - In progress by @rdubrock
• [x] Allow users to do async multi-http - i.e. a response from one can be passed to another - DONE by @rdubrock

Phase 1: Script editor

• [ ] Build a script editor, that will allow users to paste a scripted check - @rdubrock is investigating/building a proof of concept

Phase 2: Browser checks

• [ ] Build browser checks into Synthetics