Remove irrelevant SVGZoomAndPan API

[queengooborg]

This PR removes the irrelevant SVGZoomAndPan API as per the corresponding data guidelines. The lack of current support has been confirmed by the mdn-bcd-collector project (v3.3.0), even if the current BCD suggests support.

[foolip]

I've confirmed with https://mdn-bcd-collector.appspot.com/tests/api/SVGZoomAndPan that SVGZoomAndPan isn't its own exposed interface in Edge 18, Chrome 80 or Safari 12.1.

It was however in Firefox 70, so it's not old enough to remove under the irrelevant features guideline. I think it should be removed anyway since it's kind of useless without also having data for the zoomAndPan properties that the constants on this interface were used for, but that would be a different kind of reason.

@ddbeck do you think we can remove this half-present and almost-old-enough-for-removal feature?

[foolip]

@queengooborg maybe you can make "zoomAndPan" attribute removal into this as well? Those are present, but the properties by the same name aren't.

[ddbeck]

@ddbeck do you think we can remove this half-present and almost-old-enough-for-removal feature?

We're what, a month off and the API is useless? Go ahead. 👍

[foolip]

Alright, breaking the rules with abandon!