set up PostgreSQL auth methods correctly in hammer

It currently sets the authentication method for local connections to trust. This works for some systems, but on Alpines, CentOSs & Fedoras:

14:54:55  [ RUN      ] PgSqlBasicsTest.boolTest
14:54:55  unknown file: Failure
14:54:55  C++ exception with description "FATAL:  Ident authentication failed for user "keatest"
14:54:55  " thrown in the test fixture's constructor.
14:54:55  [  FAILED  ] PgSqlBasicsTest.boolTest (5 ms)

https://jenkins.aws.isc.org/job/kea-dev/job/ut-extended/436

As doc/devel/unit-tests.dox points out, both local and host connections should have their authentication methods set to password.

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