Split pgsql::database into pgsql::database::create and pgsql::database::populate

refs #6842
Outsource 'icinga_unittest' database creation into pgsql::database::create

refs #6842
Outsource 'icingaweb' database creation into pgsql::database::create

refs #6842
The name of pgsql::database::create MUST NOT be create-pgsql-*-db
Split mysql::database into mysql::database::create and mysql::database::populate

refs #6842
Make privileges customizable in mysql::database::create (and mysql::database::populate)

refs #6842
Outsource 'icinga_unittest' database creation into mysql::database::create

refs #6842
Outsource 'icingaweb' database creation into mysql::database::create

refs #6842
Outsource 'icing_web' database creation into mysql::database::create

refs #6842