We need to ask users to give their consent to storing cookies and making use of web analytics tools in the donation application. Please see the [document on Figma](https://www.figma.com/file/4Zrj2RQlGXtNs4Up5sB9L7/Consent-Feature-Designs?node-id=10%3A0) for the design.
**Acceptance Criteria**
* If a user hasn't given their consent already, a banner is shown at the bottom of the page asking for it.
* The banner contains a headline, a paragraph of further explanation and two buttons:
* One button to give consent to all cookies and web analytics features ("Alle akzeptieren")
* One button to customize ("Cookies überprüfen")
* Clicking the customization button expands the banner and shows the available options:
* The first entry is for essential cookies that are required to make the basic functionality (and our processes) work. The checkbox is always checked and cannot be unchecked.
* The second entry is for non-essential cookies and web analytics. The checkbox is not checked by default.
* Clicking "Cookies speichern" stores the user's choice.
* Clicking "Alle akzeptieren" stores the user's consent to all cookies and web analytics.
* There is a chevron icon at the top right of the expanded banner. Clicking on it collapses it and shows the initial banner again.
* The consent banner does not block users from donating by adding space at the bottom of the page.
* When closing the consent banner, the reserved space at the bottom is removed.