add make install target

Installation includes PHP andPython libraries, settings, the basic
country data, the postgresql module and our custom version of
osm2pgsql. The latter is installed in our private library directory
so that it does not get in the way of a potentially installed
osm2pgsql from the distribution.

cmake/tool-installed.tmpl

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+import sys
+import os
+
+sys.path.insert(1, '@NOMINATIM_LIBDIR@/lib-python')
+
+os.environ['NOMINATIM_NOMINATIM_TOOL'] = os.path.abspath(__file__)
+
+from nominatim import cli
+
+exit(cli.nominatim(module_dir='@NOMINATIM_LIBDIR@/module',
+                   osm2pgsql_path='@NOMINATIM_LIBDIR@/osm2pgsql',
+                   phplib_dir='@NOMINATIM_LIBDIR@/lib-php',
+                   sqllib_dir='@NOMINATIM_LIBDIR@/lib-sql',
+                   data_dir='@NOMINATIM_DATADIR@',
+                   config_dir='@NOMINATIM_CONFIGDIR@',
+                   phpcgi_path='@PHPCGI_BIN@'))