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/tests/tnc/tnccs-20-ev-pt-tls/test.conf

@@ -22,7 +22,7 @@ IPSECHOSTS="carol moon dave alice"
 
 # Guest instances on which databases are used
 #
-DBHOSTS="alice"
+DBHOSTS="alice carol"
 
 # charon controlled by swanctl
 #