Add yotta config section to pxt.json doc page

[ganicke]

Some DAL config examples/description added to the pxt.json page.

Not sure if this is correct, but I 'yotta' know by now.

Closes microsoft/pxt-microbit#5329

[jwunderl]

LGTM

[bsiever]

👍 for the"'yotta' know"

[bsiever]

One issue that triggered this was about the interplay between bluetooth security settings, the values inherited by extensions, and the UI behavior in MakeCode. Specifically, I have an extension that's doing:

  "yotta": {
        "config": {
            "microbit-dal": {
                "bluetooth": {
                    "open": 1
                }
            }
        }
    }

I think there's a compelling reason for open security for my extension, as described here: microsoft/pxt-microbit#5202 (comment) , but Martin (@martinwork) discovered some unusual behavior in the UI.