introduce jinja2 for preprocessing SQL

Replaces various hand-crafted replacements of varying format with
a single Jinja2 templating mechanism. Allows full access to
configuration if necessary.

lib-sql/functions.sql

@@ -0,0 +1,20 @@
+{% include('functions/utils.sql') %}
+{% include('functions/normalization.sql') %}
+{% include('functions/ranking.sql') %}
+{% include('functions/importance.sql') %}
+{% include('functions/address_lookup.sql') %}
+{% include('functions/interpolation.sql') %}
+
+{% if 'place' in db.tables %}
+    {% include 'functions/place_triggers.sql' %}
+{% endif %}
+
+{% if 'placex' in db.tables %}
+    {% include 'functions/placex_triggers.sql' %}
+{% endif %}
+
+{% if 'location_postcode' in db.tables %}
+    {% include 'functions/postcode_triggers.sql' %}
+{% endif %}
+
+{% include('functions/partition-functions.sql') %}