changed volume paths ; FLAT_NODES=enabled (#261)

Changes:
- /var/lib/postgresql/14/main/            => /data/database/
- /var/lib/mod_tile/                      => /data/tiles/
- /home/renderer/src/openstreetmap-carto/ => /data/style/
- /data.osm.pbf                           => /data/region.osm.pbf
- /data.poly                              => /data/region.poly
- /nodes/flat_nodes.bin                   => deprecated (use FLAT_NODES=enabled instead)

Because some files are needed later and should never be separated from the database, the import does save those files now into /data/databases/:
- /data/database/region.poly
- /data/database/flat_nodes.bin
- /data/database/planet-import-complete
- and automatic update artifacts

.github/workflows/build-and-test.yaml

@@ -26,7 +26,7 @@ jobs:
     env:
       VOLUME    : osm-db
       CONTAINER : osm-www
-      MOUNT     : /var/lib/postgresql/14/main
+      MOUNT     : /data/database/
     steps:
     -
       name: Checkout