Input text: add an official way to add static or interactive icons appended inside the input

[imagoiq]

For example a search icon is often added to filter forms:

TBD: in the internet-header, it is used as a button. How to differentiate both? Should we allow icons to be append to input?

[gfellerph]

@imagoiq have a look at https://www.figma.com/file/xZ0IW0MJO0vnFicmrHiKaY/Components-Post?type=design&node-id=16739%3A53259&mode=design&t=uFqiwSCwgBx3yCuO-1. This will be the new search field.

Another approach would be adding the generic possibility to add pre- and postfixes to input fields (https://www.figma.com/file/xZ0IW0MJO0vnFicmrHiKaY/Components-Post?type=design&node-id=10657%3A50263&mode=design&t=uFqiwSCwgBx3yCuO-1).

The datepicker is a similar use case.

• [x] refine with the Design Team

[gfellerph]

Design is ready

[gfellerph]

• [ ] check for accessibility support and <input type="search">

[gfellerph]

Closing in favor of #3351