refacto: reorganize folder tree to split lora gateway stack from app

Those stack won't necessarily be on the same host, so they need to be
split

lora-gateway/configuration/postgresql/initdb/001-chirpstack_extensions.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -e
+
+psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --dbname="$POSTGRES_DB" <<-EOSQL
+    create extension pg_trgm;
+    create extension hstore;
+EOSQL