This is a code simplification for distributions that don't change the
PostgreSQL version in a major release. As a bonus fact, it adds support
for CentOS 8 Stream which identifies itself without a minor version.

For completeness, the OS facts from CentOS 8 Stream:

    # facter os
    {
      architecture => "x86_64",
      family => "RedHat",
      hardware => "x86_64",
      name => "CentOS",
      release => {
        full => "8",
        major => "8"
      },
      selinux => {
        enabled => false
      }
    }

Both branches of the selector have the same version so it's redundant.

FreeBSD uses Postgresql 12 by default
Ref: https://svnweb.freebsd.org/ports/branches/2021Q1/Mk/bsd.default-versions.mk?revision=560000&view=markup#l100

(IAC-1337) - Release version v6.9.0

Set default PostgresQL version for FreeBSD

When password is not set, `{ 'PGPASSWORD' => password } unless
password.nil?` evaluates to `nil`, setting `env_hash` to `nil`.

`nil` is then passed as the first argument of `Open3.capture3` which
result in an exception:

```
/opt/puppetlabs/puppet/lib/ruby/2.7.0/open3.rb:213:in `spawn': no implicit conversion of nil into String (TypeError)
	from /opt/puppetlabs/puppet/lib/ruby/2.7.0/open3.rb:213:in `popen_run'
	from /opt/puppetlabs/puppet/lib/ruby/2.7.0/open3.rb:101:in `popen3'
	from /opt/puppetlabs/puppet/lib/ruby/2.7.0/open3.rb:281:in `capture3'
	from /opt/puppetlabs/mcollective/tasks-spool/899e9e0635bb53f1a09b4716548ff69f/files/sql.rb:13:in `get'
	from /opt/puppetlabs/mcollective/tasks-spool/899e9e0635bb53f1a09b4716548ff69f/files/sql.rb:27:in `<main>'
```

Make sure `env_hash` is always a hash to fix this issue.

Clean up globals logic to support CentOS 8 stream

Fix postgresql::sql task when password is not set

pdksync - Update gha templates

(IAC-1136) Back out CentOS 8 tests on TravisCI

(bug) reload the service after the deletion of old unit file

(IAC-1408) Release Prep v6.10.0