[server/session] add missing rollback when freeing a db connection
When we let go of a cnxset and give it back to the pool, we need to make
sure it's not in the middle of a transaction.
We got bitten by a migration where the connection used by admin's
repo.connect was not rolled back before attempting the migration,
causing a deadlock because it had a lock on a table. This could
potentially also be an issue for e.g. hooks or looping tasks that didn't
explicitly rollback before calling free_cnxset or moving out of a
ensure_cnx_set block.
Add some entities
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As manager, you can access to entity creation forms by using the `site management`_ page.
.. _`site management`: manage
As regular user, the index page or the action box may propose some links to create entities according to the context.