testing: Move collector.db in tnc/tnccs-20-ev-pt-tls scenario to /etc/db.d

Also move initialization to the pretest script (it's way faster in the
in-memory database).

testing/hosts/default/usr/local/bin/init_collector

@@ -1,4 +1,4 @@
 #! /bin/sh
 
-cat /usr/local/share/strongswan/templates/database/sw-collector/sw_collector_tables.sql | sqlite3 /etc/pts/collector.db
+cat /usr/local/share/strongswan/templates/database/sw-collector/sw_collector_tables.sql | sqlite3 /etc/db.d/collector.db
 LEAK_DETECTIVE_DISABLE=1 /usr/local/sbin/sw-collector