Slow/long load times of district map.

[NXXR]

The district map takes significant time to load. Poking around on the website, it seems the Response from the Backend API takes way too long to generate. https://zam10063.zam.kfa-juelich.de/api/v1/rki/2024-03-02/?all&groups=total&compartments=MildInfections was the request I tested, which is used to request the infection data for a single day in order to fill the district map. The request was completed after 25-26 seconds, which is unreasonably long for roughly 100kb of data.

@annawendler you poked around in the backend a little, did you come across anything that would warrant this much time to be necessary to compile the response?

I reckon either the request has a mistake somewhere in the query that causes misses to delay the response or the database is badly indexed to delay the response.