chore(test): set connection lifetimes for postgresql (#8586)

# Which Problems Are Solved

defaults.yaml only specifies defaults for cockroach. Therefore, options
omitted for postgresql are actually set to `0`.
This means that the connections timeouts are set to `0` and connections
were not reused, resulting in a performance penalty while running the
integration tests.

# How the Problems Are Solved

Set MaxConnLifeTime and MaxConnIdleTime options in postgres


# Additional Changes

- none

# Additional Context

- none

Co-authored-by: Silvan <silvan.reusser@gmail.com>
Co-authored-by: Livio Spring <livio.a@gmail.com>

internal/integration/config/postgres.yaml

@@ -7,6 +7,8 @@ Database:
     Database: zitadel
     MaxOpenConns: 20
     MaxIdleConns: 20
+    MaxConnLifetime: 1h
+    MaxConnIdleTime: 5m
     User:
       Username: zitadel
       SSL: