Introduce new get_psql_info task

Reuses library from facter that can report the major version of PSQL
installed

Author: ody

tasks/get_psql_version.json

@@ -0,0 +1,5 @@
+{
+  "description": "Run on a PE PSQL node to return the major version of the PSQL server currently installed",
+  "parameters": { },
+  "input_method": "stdin"
+}

tasks/get_psql_version.rb

@@ -0,0 +1,24 @@
+#!/opt/puppetlabs/puppet/bin/ruby
+# frozen_string_literal: true
+
+require '/opt/puppetlabs/puppet/cache/lib/pe_install/pe_postgresql_info.rb'
+
+# GetPEAdmConfig task class
+class GetPSQLInfo
+  def initialize(params); end
+
+  def execute!
+    psql_info = PEPostgresqlInfo.new
+    data = { 'version' => psql_info.installed_server_version }
+    puts data.to_json
+  end
+end
+
+# Run the task unless an environment flag has been set, signaling not to. The
+# environment flag is used to disable auto-execution and enable Ruby unit
+# testing of this task.
+unless ENV['RSPEC_UNIT_TEST_MODE']
+  Puppet.initialize_settings
+  task = GetPSQLInfo.new(JSON.parse(STDIN.read))
+  task.execute!
+end