Switch maas to dockerized PostgreSQL

remove database port hardcode
extend tests with new port parameter
added backward compability for port parameter

Prod-related: PROD-25203  (PROD:25203)

Change-Id: Id25c30e1e9a2710c1567ffa10e453c1964c732da
diff --git a/metadata/service/region/single.yml b/metadata/service/region/single.yml
index 6700acc..54ac038 100644
--- a/metadata/service/region/single.yml
+++ b/metadata/service/region/single.yml
@@ -18,4 +18,5 @@
         name: maasdb
         password: password
         username: maas
+        port: 5432
       enabled: true