Postgresql tables seem duplicated (with suffixes such us pkey, hashes, etc)
No, those are not "duplicated", those are additional relations/objects created for the tables.

reversion_revision_pkey is most probably the unique index supporting the primary key for the table reversion_revision. 

And the others are most probably indexes as well. 

You can add this expression to your query to see the actual type of the relation:

case relkind
   when 'r' then 'table'
   when 'i' then 'index'
   when 'S' then 'sequence'
   when 'v' then 'view'
   when 'm' then 'materialized view'
   when 't' then 'TOAST table'
   else relkind
end as rel_kind





  I imagine it should be enough with deleting this "duplicated" tables


No, do not delete (drop) those. They are essential for your database to work.



For a description on all columns in pg_class see here