[tabs] fix pb with non-lazy tabs: style isn't properly set due to missing jquery.ui activation. Closes #2465657 also do a small cleanup on the way, and properly implements render_entity rather than cell_call, as one would expect regarding default PrimaryView code.

[migration] fix backward compat for rename_relation

[datafeed] make cnxset handling of datafeed source more robust currently we may run in some cases where the session has no more cnxset depending on errors and parser's handling of the cnxset. Also, free the cnxset and reacquire it later, letting a chance to other threads to run.

don't use rset.rowcount in predicates, this makes them usable with other types such as lists

[c-c db-check] don't skip is/is_instance_of mandatory relation to avoid telling two opposite messages when the relation is missing. Closes #2465659

[ui tabs] avoid duplicate rset argument if already specified in tab kwargs. Closes #2464786

[entity edition] don't remove values from attribute cache on the repository side This follows changesets 552de9f0c46d, 1527b012802f, 25da1e5c7c50 and 4ba11607d84a. closes #2423719 ?

fix ldapuser test

Prepare 3.15.4

migration: replace empty passwords with random ones on upgrade