Move pgbouncer password alias to the main configuration

it avoids a different behavior between the censored and uncensored environments

Depends on infra/puppet/puppet-swh-private-data-censored!2 Depends on !76 (closed)

Test Plan

diff origin/production/belvedere.internal.softwareheritage.org current/belvedere.internal.softwareheritage.org
*******************************************
  Concat::Fragment[postgres] =>
   parameters =>
     content =>
      - "postgres" "md5e8a48653851e28c69d0506508fb27fc5"
      + "postgres" "md571ca878e371146a35722783d442fadd0"
      _
*******************************************
  Concat_fragment[postgres] =>
   parameters =>
     content =>
      - "postgres" "md5e8a48653851e28c69d0506508fb27fc5"
      + "postgres" "md571ca878e371146a35722783d442fadd0"
      _
*******************************************
  Pgbouncer::Userlist[pgbouncer_module_userlist] =>
   parameters =>
     auth_list =>
      - [{"user"=>"postgres", "password"=>""}]
      + [{"user"=>"postgres", "password"=>"swh::deploy::db::postgres::password"}]
*******************************************
*** End octocatalog-diff on belvedere.internal.softwareheritage.org

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Migrated from D4565 (view on Phabricator)