This makes Nominatim compatible with osm2pgsql's default update
modus operandi of deleting and reinserting data. Deletes are diverted
into a TODO table instead of executing them. When data is reinserted,
the corresponding entry in the TODO table is deleted. After updates are
finished, the remaining entries in the TODO table are executed, doing
the same work as the delete trigger did before.
The new behaviour also works against the gazetteer output with its
insert-only mechanism.
Drops all calls to PHP utility functions. nominatim cli functions
are used where possible, to stay as close to the final code as
possible with the tests.
By removing the PHP calls, the test code now only uses osm2pgsql and
the database module from the build directory.
Put the connection to the test database into auto-commit mode
and get rid of the explicit commits. Also use cursors always in
context managers and unify the two implementations that copy
data from the place table.
