Improve A11y

[devtobi]

PrimeVue components offer documentation on how to properly do a11y with them.
Additionally tooling like vue-a11y can be introduced to check.

• Setup Tooling: https://vue-a11y.github.io/eslint-plugin-vuejs-accessibility/ and Add example in documentation for vue 3 typescript with import instead of require vue-a11y/vue-axe-next#6
• Check different states of app with tools like Lighthouse
• Improve HTML templating where necessary

[devtobi]

I successfully setup the tooling, however due to some limitations of PrimeVue, not all a11y issues can be fixed. Those things should be reported to PrimeVue team