Refactor / improve duplicate-id-aria

[WilcoFiers]

With the duplicate-id and duplicate-id-active rules deprecated in 4.8, it would be useful for us to look at how we can improve duplicate-id-aria. There are two things I'd like to see us figure out:

1. Can we make this rule faster if instead of starting from IDs we start from IDREF attributes. I don't know if that needs to be a different rule. We'll have to decide if having the same rule report all different nodes is better than having a new rule do it, and turning the current rule off. Up for debate.

2. Can we further reduce noise, and maybe make this rule more accurately by looking at DOM position, and the accessible name of the elements referenced. In particular the for labelledby / describedby if all nodes with the duplicated ID have the same accessible text, we could pass the rule since the control will (almost certainly) have the correct name.

[MelSumner]

Since duplicate IDs are technically allowed in SVGs, would it be useful to not check the element if it's an SVG?

[backwardok]

I like the idea of point 1 so that axe only reports on ids that are being referenced. Also big +1 to point 2 since this has actually come up recently for me where there are duplicate ids for an aria-describedby reference that have identical content (where it isn't an actual issue for a user). Would love to not have it flag when it's not a real issue that a user would come across.