osm import to postgresql via osm2pgsql with --output=flex option to provide a better table layout

[astrid_emde]

With the script load_postgis.sh we import the osm data to PostgreSQL see

​https://github.com/OSGeo/OSGeoLive/blob/master/bin/load_postgis.sh#L104

From osm2pgsql 1.3.0 version there is a new mode for export that is very flexible and the new way to use osm2pgsql (--output=flex) see

​https://osm2pgsql.org/doc/manual.html#the-flex-output

We could use this flex mode for the osm data import. This would enable us to provide tables that have a more reasonable layout.

Here you can find some lua configuration file examples: ​https://github.com/openstreetmap/osm2pgsql/tree/master/flex-config

We would have to discuss whether this is a good change and see which other projects/quickstarts are effected. I guess it is a milestone for OSGeoLive 15

[darkblueb]

one piece of wisdom here may be " Create what the rendering/querying engine expects"