We don't want runUnitTest is to listen on 127.0.0.1, as it is not
allowed for SlapOS instances. Another reason for the change is because
we are using userhosts, name resolution of localhost was done on DNS
server and not all DNS server resolves localhost.

Because zelenium tests needs to access this zserver over a secure
origin, add an https proxy in the balancer for tests.

Document the existing behavior that setting mariadb.test-database-amount
to 0 disable the creation of testrunner, now that it also controls the
generation of one balancer entry.