Display place selection in comparison page

[x] Add a two-sided place search
[x] Make sure that meta information of selected place (e.g. latitude, longitude, place name) are obtained so that they can be used in other components

See comparison page as sketched in the Figma prototype.

If possible try to limit the places to the cities we currently support. Make sure that meta information of selected place (e.g. latitude, longitude, place name) are obtained so that they can be used in other components.

See https://github.com/mapbox/mapbox-gl-geocoder/blob/main/API.md

open-public-transport / open-public-transport-frontend

Display place selection in comparison page #20