Remove commented style rule.
Add osm2pgsql style file to the repo.

The style file is inextricably linked with the style rules, much
more so than the version of osm2pgsql used. This allows us to add
or remove columns without requiring users to change their (perhaps
packaged) version of osm2pgsql.

Changes to this file usually requires reloading of databases, so
they will often be accompanied by major version increments.