Implement an "x to close" dialog option

Gonna work on it.

Added theming functions for dialog content header and buttons. What will be useful for custom theme developers.
Added close button which triggers customEvent with bubble.

Also added small code improvements.

1. Core version +11
2. Grouped dialog settings like

    if (settings.width) {
      if (Number.isInteger(settings.width)) {
        dialogContainer.style.setProperty('width', `${settings.width}px`);
      } else {
        dialogContainer.style.setProperty('width', settings.width);
      }
    }

TO:

    [
      'width',
      'height',
      'minWidth',
      'maxWidth',
      'minHeight',
      'maxHeight'
    ].forEach(dimension => {

Added a few comments, couldn't review completely yet.

Great stuff!! Thanks a lot @finnsky!

I guess we still should add some styling to the close button, currently it is quite lackluster. Is there any drupal native "x" button, where we could clone the styling from?
Furthermore, it might make sense to have an optional parameter for the close button in "Drupal.theme.dialogHeader". I am not a theming expert, but this would only make sense to me.

Otherwise, LGTM!

Let's move the styling part to 📌 The styling of the dialog element needs adjusting. Active .

@finnsky we could also create a follow-up ticket for only styling the close button, feel free to decide yourself here.

Thank you for review.

it might make sense to have an optional parameter for the close button in "Drupal.theme.dialogHeader".

in fact `Drupal.theme.dialogHeader"` it is the option for theme developer for overriding header.

On my side i would better to move with webcomponent and slots.

Alright! I am not too knowledgeable on Drupal theme development, just was something I thought would make sense hear.

RTBC then!

Automatically closed - issue fixed for 2 weeks with no activity.