refactor: cursor pointer for clickable elements/components

[annsch]

As discussed before, we like to ensure that every clickable element has cursor: pointer (buttons, accordion, etc.)

• [ ] adr must be updated
• [x] global solution (init.scss or placeholder, ...)
• [x] get an explicit scope of these elements by creative colleagues, our suggestions:
  • [x] input
  • [x] label
  • [x] textarea
  • [x] button
  • [x] summary

[mfranzke]

Defining the exact scope of "clickable elements" is key on this topic, as e.g. an input is clickable also as well as a label.