fix(NcRichContenteditable): make autocomplete accessible

[ShGKme]

☑️ Resolves

• Fix [BITV] 9.4.1.2/3.8 - In the "Details" section under the "Activity" tab, it is possible to open a dropdown list when entering "@", ":" or "/" into the textbox, for example, to select from a list of emojis. (2) nextcloud/server#41896

The solution may look a bit complex with dirty places, but I see no better solution except forking Tribute.js.

Complex parts with tribute:

• No event for "tribute is open"
  • tribute-active-true does not respect async loading
• No event for "selection changed" or method to get currently selected item
  • Needed for activedescendant
• When tribute is closed, it is still in the DOM with the old list. On open you first have an old list and then it loads a new actual list (which might be different)
• If you have many tributes on an element, you cannot get one that was active on tribute-active-true event. Tribute is supposed to be used only once on element
• If you are using 1 Tribute for many collections, containerClass is not updating on opening another collection (known Tribute.js issue)

refactor(NcRichContenteditable): create 1 tribute for all autocompletes

• Fixes Tribute was already bound to DIV warning
• Tribute is supposed to be only once on the element
• Simplifies further work with Tribute

refactor(NcRichContenteditable): move constants out of reactive data

Not required, but simplifies work with actual component's state.

• smilesList is always a constant and reused across all the instances
• tribute options are used only once to initialize tribute

refactor(NcRichContenteditable): cancel autoComplete on close

• Correctly implement debounced method, so that debouncedFunction properties are available and each component instance has its own debounce.
  • Defining method as debounced is not valid in Vue. In this case, we have 1 shared debounce for all component instances.
• Clear debounce on autoComplete close
  • Otherwise, if you closed autocomplete for fast and then reopen another one, you may receive data from the previous autocomplete after debounce timeout.

fix(NcRichContenteditable): make autocomplete accessible

• Set aria-* attributes to the contenteditable
• Set aria-activedescendant to connect with the current selected element from autocomplete
• Make the list of options listbox + option instead of native list + listitem
  • list doesn't work as a list of options for screen reader

fix(NcRichContenteditable): provide focus-visible class

• For further work - allows to set styles for keyboard navigation, emulating :focus-visible

🖼️ Screenshots

🏚️ Before	🏡 After
Contenteditable:	.
Options list	.
Ignored

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable

[JuliaKirschenheuter]

tested and works with screen reader!

[susnux]

Awesome work! 🚀

[ShGKme]

The only thing added during the force push.

To set up integration only once after the first open, not each time.

[ShGKme]

Sorry for a fast merge, rushing to get this in the tomorrow's release. Feel free to review merged, I'll have a look.