tControl: Provide optional IED name in findControlSubscription

[danyill]

It would be useful to me if I could provide an optional IED name in findControlSubscription to reduce the query scope.

I note in passing the current query is very broad

https://github.com/OpenEnergyTools/scl-lib/blob/5657a7104df333eb505a3ef99a4b36772494a64e/tControl/findControlSubscription.ts#L8-L10

We could use a more performant alternative:

https://github.com/OpenEnergyTools/scl-lib/blob/5657a7104df333eb505a3ef99a4b36772494a64e/tFCDA/removeFCDA.ts#L18-L23

[danyill]

I'm using something like this:

function findControlBlockSubscription(
  control: Element,
  toIedName: string
): Element[] {
  const doc = control.ownerDocument;
  const fromIedName = control.closest('IED')?.getAttribute('name');

  return Array.from(
    doc.querySelectorAll(
      `:root>IED[name="${toIedName}"]>AccessPoint>Server>LDevice>LN0>Inputs>ExtRef[iedName="${fromIedName}"], 
      :root>IED[name="${toIedName}"]>AccessPoint>Server>LDevice>LN>Inputs>ExtRef[iedName="${fromIedName}"]`
    )
  ).filter(extRef => matchSrcAttributes(extRef, control));
}