project init

[Tschonti]

notes:

• next 15 comes with react 19rc, which is not stable. Should we roll back to react 18?
• react-leaflet v4 (stable) doesn't work with react v19 (though for me it didn't work with react v18 either), so I used v5rc, that's also not stable
• the map container needs a workaround to prevent next from even trying to render it on the server
• the colors and components defined in the figma can't be transferred exactly to a nextUI theme, since nextUI uses opacity for hover and disabled effects, thus you can't make a button darker on hover. Maybe we should create custom button components to match our Figma better