As much as possible I would like us to avoid having to go the with a global event listener on click/mouseover. For now I have removed all cases of `data-tooltip`, if we clearly identify a use case of a global event listener we might reconsider this.
The following changes are also included:
- by default tooltips won't attempt to focus first focusable element anymore
- tooltip will now use `cursor: pointer` by default
- a new service has been introduced: `InternalTooltip` which is responsible to track the current instance displayed by a `<DTooltip />`. Portal elements when replaced are not properly cleaned and I couldn't figure out a way to have a proper hook to ensure the previous `DTooltipInstance` is properly set as not expanded; this problem was very visible when using a tooltip as interactive and hovering another tooltip, which would replace the interactive tooltip as not closed.
1. Use `this.` instead of `{{action}}` where applicable
2. Use `{{fn}}` instead of `@actionParam` where applicable
3. Use non-`@` versions of class/type/tabindex/aria-controls/aria-expanded
4. Remove `btn` class (it's added automatically to all DButtons)
5. Remove `type="button"` (it's the default)
6. Use `concat-class` helper
This PR is the first step towards replacing our `{{user-selector}}` and eventually deprecating and removing it from our codebase. Some of `{{user-selector}}` problems are:
1. It's called `{{user-selector}}`, but in reality in can also select groups and emails.
2. It's an Ember component, yet it doesn't have a handlebars template and uses jQuery to render itself and modify the DOM. An example of this problem is when you want to clear the selected users programmatically, see [this](6c155dba77/app/assets/javascripts/discourse/app/components/user-selector.js (L179-L185)).
3. We now have select kit which does very similar things but a lot better.
This PR introduces `{{email-group-user-chooser}}` which is meant to replace `{{user-selector}}`. It extends select kit and has the same features that `{{user-selector}}` has. `{{user-selector}}` is still used in a few places in core, but they'll all be replaced with the new component in a separate commit.
Once `{{user-selector}}` is not used anywhere in core, it'll be deprecated and then removed after the 2.7 release.
