Invalid geometry error during `ohsome-planet changesets` parsing due to `LANG` beeing set to `de_DE.UTF-8`

```sh
echo "export LANG=de_DE.UTF-8" >> ~/.bashrc
source ~/.bashrc
java -jar ohsome-planet-cli/target/ohsome-planet.jar \
changesets \
--bz2 changesets-260112.osm.bz2 \
--changeset-db "jdbc:postgresql://localhost:5432/postgres?user=$OHSOME_PLANET_DB_USER&password=$OHSOME_PLANET_DB_PASSWORD" \
--create-tables
```
Leads to this error:
```
Caused by: org.postgresql.util.PSQLException: ERROR: parse error - invalid geometry
Hint: "SRID=4326;POLYGON((13,06" <-- parse error at position 24 within geometry
Where: COPY changesets, line 1, column geom: "SRID=4326;POLYGON((13,066414 47,811554, 16,387561 47,811554, 16,387561 48,227182, 13,066414 48,22718..."
```
When `LANG` is set to `en_US` above command works without error.

Reproduce the failure with the provided `ohsome-planet changesets` command under `LANG=de_DE.UTF-8`, then compare it with `LANG=en_US`. Trace the changesets parsing and geometry serialization path to find where locale-sensitive decimal formatting enters the PostgreSQL geometry value. Done means parsing succeeds independently of the system locale; add or run a regression check if the relevant test location is found.

Written by the indexing model from the issue text.