Global/Component styling

[x] check out https://opensource.adobe.com/spectrum-css/get-started.html (not suitable for our use case/time) Prepare styled components as follows:
[x] outlined button
[x] make buttons (button and a.button) animated on hover by default
[ ] select boxes as per https://summit-emea.adobe.com/emea/registration/
[x] adobe fonts (adobe clean, ...)

...more to come

adobe-basel / summit-emea-team-3