feat(tIED): allow IED removal (closes #91).

[danyill]

Closes #91

As always, I would be very grateful for a review.

I'm not removing supervisions using the inbuild unsubscribe functionality because it's implemented "the wrong way" (removal of LNs or DOIs when I want removal of the GoCBRef/SvCBRef > Val's text content). I hope that's acceptable for now.

While I could mostly reuse the test structure for the updateIED code (thank you!), I have redone the test files as I needed the subscriptions and supervisions to be more realistic.

Once we have this right, I'd be keen for a new release as I have a menu plugin that I would like to provide in our distribution to allow IED removal.

[danyill]

Currently, this does not remove empty SubNetwork elements if we are removing the last ConnectedAP.

I guess we could do something like the following but I worry about over-reach. And I guess we could make it an option. Perhaps we could just wait until it's a problem for someone :wink:

function removeWithIedName(ied: Element, iedName: string): Remove[] {
  const selector = elementsToRemove
    .map((iedNameElement) => `${iedNameElement}[iedName="${iedName}"]`)
    .join(",");

  return Array.from(ied.ownerDocument.querySelectorAll(selector))
    .filter(isPublic)
    .map((element) => {
      if (
        element.tagName === "ConnectedAP" &&
        element.parentElement!.querySelectorAll("ConnectedAP").length === 1
      ) {
        return { node: <Element>element.parentElement };
      }
      return { node: element };
    });
}

[JakobVogelsang]

I think an issue marking the fact that the removeIed does not clean the DataTypeTemplates section would also be nice. I don't think we should have that from the beginning, but a reminder is nice to have.

[danyill]

Thank you for this review, I have made some updates.