Milestone 2jb Accessibility of contacts pane

[timea-solid]

Contacts-pane todos for accessibility:

TODO:

• adding HTML5 and ARIA labels
• add accessibility tests based on 'axe-core' (example here)
• making sure it also work when resizing screen
• making sure other accessibility features are inline with the WCAG standard (the tests will show). As example: text sizes, button sizes, keyboard focus and so on.

[timea-solid]

Started by adding a local dev setup: SolidOS/contacts-pane#184