(Low Prio) Phone Input improvement

[Adam3371]

Why

In order to provide a user with a even better UX when authenticating with phone number, here are some improvements that can be made.

TODOS

• Make it possible to select country code by using Tab, Arrows and Enter Keys.
• Don't allow any other characters than "+", and digits
• Keep search bar on top when scrolling
• USA, Germany, India, GB on Top (KP: not sure about that probably skip)
• Once BE ready, pre-select the country code of the user

Acceptance criteria

• It is possible to select a country code without using the mouse
• Only digits and "+" are accepted in the input field
• When scrolling, search bar stays on top