(PE-37178) bionic tests - install pg from archive

Ubuntu 18 went EOL in May 2023, so it no longer has official pgdg repos
for its packages. Setup the archive repo so tests can continue to be run

Author: austb

acceptance/suites/pre_suite/foss/95_install_pdb.rb

@@ -10,6 +10,15 @@
   on(master, "rm -f #{sitepp}")
 end
 
+step 'Update Ubuntu 18 package repo' do
+  if master.platform =~ /ubuntu-18/
+    # bionic is EOL, so get postgresql from the archive
+    on master, 'echo "deb https://apt-archive.postgresql.org/pub/repos/apt bionic-pgdg main" >> /etc/apt/sources.list'
+    on master, 'curl https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -'
+    on master, 'apt update'
+  end
+end
+
 step 'Install Puppet nightly repo' do
   install_puppetlabs_release_repo_on(master, 'puppet7-nightly')
 end
@@ -23,10 +32,12 @@
 end
 
 step 'Configure PuppetDB via site.pp' do
+  manage_package_repo = ! master.platform.match?(/ubuntu-18/)
   create_remote_file(master, sitepp, <<SITEPP)
 node default {
   class { 'puppetdb':
-    manage_firewall => false,
+    manage_firewall     => false,
+    manage_package_repo => #{manage_package_repo},
   }
 
   class { 'puppetdb::master::config':