Add dialog html tag.

[Johann-Goncalves-Pereira]

Recently, the super useful HTML tag get full support as you can see:

• https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog
• https://caniuse.com/?search=dialog%20

So, I made this as an open-source contribution.

[BenAttenborough]

Be really cool if Elm ever got updates

[ultrox]

Untill this modules updates here is link how to implement it in user land with ports https://www.lindsaykwardell.com/blog/native-dialog-in-elm

[laurentpayot]

@ultrox I tried to use dialog as described in the Lindsay Wardell blog post. It works well but:

• It uses one port.
• You cannot close the modal by clicking outside it.
• You cannot replay the modal opening in the debugger (opening does not depend on the model, although you could easily fix that).

I ended up using a custom element. There is an example in this Elm discourse post.