Update 'Functional Testing' section to Playwrite

[jburns24]

Currently this section uses selenium which is still out there but dated. We have been doing Playwright more with clients and it has since become the more popular e2e testing framework.

[Labreo]

Hello @jburns24 . I would like to work on the issue. Would require changes to the example(what is playwright what it allows to do and exercise 1.(displaying playwright functional testing code) and 2.(interchanging it with selenium) sections.
Also could add a smaller section below to talk a bit about what the playwright MCP server is and how to use it.

[jburns24]

@Labreo Please feel free to take a stab, some of this has already been done in #748

I will say there is some research I was hoping to do around the MCPs functionality. Was hoping to ultimately see if it was an effective tool to enable your agent to leverage e2e testing in the development loop.

Feel free to play with this tool, get creative and curious to see what kind of agent workflows you can come up with.

[jburns24]

Playwright MCP research moved to #771