[BITV] Accessibility related findings

[PVince81]

From times to times I'm testing with the orca screen reader from https://app.vagrantup.com/inclusivedesign

Instead of keeping local notes I'll use this ticket to dump whatever I've found so far. We can either fix some right away or raise tickets to discuss.

• [ ] in some popup menus (like talk app top bar) the screen reader says "leaving main content" when going through menu items in talk menu
  • probably because the menu DOM is outside, maybe setting menu/menuitem roles there will help
• [ ] read "Avatar of XYZ" when touching avatar component ? should we read initials ?

multiselect comments moved here: https://github.com/nextcloud/nextcloud-vue/issues/2504

[JuliaKirschenheuter]

moving this issue to "descoped" because not relevant for now