fix migration from pre-3.13.1 versions (closes #2846978) Need to check the existence of the asource column before the first call to eid_type_source.

[constraint] more robust unicity constraint failures reporting for end-users Postgres or Sqlserver have limits on the index names (around resp. 64 and 128 characters). Because `logilab.database` encodes the `unique together` constraint rtypes in the index names, we sometimes get truncated index names, from which it is impossible to retrieve all rtypes. In the long run, the way such index are named should be changed. In the short term, we try to reduce the end-user confusion resulting from this design flaw: * in source/native, the regex filtering ``IntegrityError`` message does not impose an `_idx` suffix, which indeed may be absent (the result being an UI message that resembles a catastrophic failure), * also we avoid including a trailing " (double quote) from the error message * in entities/adapters, the well-named ``IUserFriendly`` adapter is made a bit smarter about how to handle missing rtypes. * the adapter also always produces a global message explaining the issue (and the fact that sometimes, the user is not shown all the relevant info) * i18n is updated Closes #2793789

[hooks/security] Streamline attributes default permission check. The current default permission on attributes delegates the check to the entity permission update policy. Since this is already checked it can be skipped. The equality comparison will work, even with a deserialized schema, because the default update perm is:: ('managers', ERQLExpression(Any X WHERE U has_update_permission X, X eid %(x)s, U eid %(u)s)) which will always be deserialized in this order (groups first). However this is a slight semantic change: entity type level 'update' permissions can now be effectively used to encode update-time rules if the default attribute permissions are used (before this change, the 'update' rules at entity type level were fired at creation time). Closes #2930861.

[test/schemaserial] swap got/expected to get nicer unittest2 diagnostics Prepares #2965518.

[repository] drop safe attribute on ``internal_cnx`` People that need to disable hook can do it explicitly anyway.

[dbapi] deprecated the dbapi

[repoapi] deprecate dbapi compat method

[testlib] deprecated the older api to access the repo.

[connection] deprecated free_cnset and set_cnxset

[session] deprecate all Connection related method on session

[session] drop dead _current_cnx_id Not used anymore for a few commit.

[session] privatise get_cnx and close_cnx The only user, repoapi now use ``new_cnx``

[doc] add documentation for the new API in test

[testlib] add an default testcase.adminaccess (and use it for default session) This adminaccess is the new offical way to get connection, and request on a repo.

[testlib] introduce a RepoAccess class to easily create connection and request Each RepoAccess hold a session for a user and three helper function to help create Connection, ClientConnection of WebRequest related to this session. related to #2920299