Fix non-collocated BOSH PostgreSQL backups

[#50664149]

The PostgreSQL backup adapter was using the Unix socket to connect to
the director's database. This worked when the database was collocated on
the same machine as the director but failed if it was on a separate
instance. To fix this we now explicitly specify the host and port to
connect to in the backup adapter.

While fixing this we also found that if the PostgreSQL and director jobs
were not collocated then the director would not have access to the
required `pg_dump` command. We have added the PostgreSQL package to the
dependencies of the director job.
Add new Rake task to upload the BOSH dev release

It has a dependency on the `release:create_dev_release` task so that you
can upload a new release for development in one command. The new task
has one argument that will rebase the release if it is anything truth-y.
Scheduled backup timestamp should always be in UTC

This was caught when the tests failed in CI because they were run on a
box in a different timezone.