feat: aria label improvements

[GeopJr]

fix: #1164

Long way to go but I'm fixing everything I can based on the Matrix feedback.

Specifically so far:

• Pressing down from the menu button would focus on the scrolledview and not its content, fixed
• On narrow mode, the sidebar reveal button did not have a tooltip text (and therefore no aria label) that described it
• Moved accessible roles to widgetclass constructor
• Fixed wrong or missing accessible roles: markupview should be 'generic' as it's a container that can have multiple widgets and not a label. richlabel became a 'label' with relations to its emojilabel
• Fixed spoiler revealing resetting the focus position to the parent, when it should be the markupview. This is a bit tricky, as I had to make it focusable, but boxes arent really. Needs more testing but I added an experiment that makes all its children labels focusable instead as a workaround
• Post avatars had the same tooltip text as post names "Open %s's profile", when they open the mini profile instead and not the full one
• added an experiment with the post buttons labels BUT, i cant make them drop the label relation with the child, even though I explicitly set the label myself 🤷