Add ldap3 to server test requirements

[pkg] bump version number so tox won't use cw from pypi

[schema] add CubicWebRelationDefinitionSchema Stop monkeypatching yams, inherit from RelationDefinitionSchema instead.

[schema] Let RQLConstraint inherit from BaseRQLConstraint instead of RQLVocabularyConstraint There is apparently no reason for RQLConstraint to inherit from RQLVocabularyConstraint as it gets its `repo_check` method from `RepoEnforcedRQLConstraintMixIn` and RQLVocabularyConstraint (which inherits from BaseRQLConstraint) actually only overrides that method. So simplify inheritance by removing a useless level of indirection. Adjust cw_unrelated_rql accordingly, where it was that RQLConstraint inherited from RQLVocabularyConstraint.

[server] unormalize source logger's name to avoid encoding errors

[entities] parameters should be given to fire_transition, else they are simply ignored

[entity] set _cw_adapters_cache in __init__ rather than on first use

fix typos and indentation in docstrings/docs

session.id → session.sessionid

[test] test page_size problem (related to #8123231)

[predicates] guard against non-integer page_size form parameter Closes #8123231

[server/test] add test for db-dump command

[server] fix db-dump with sqlite 'gzip -c dbname > backupfile' needs to go through the shell.

[serverctl] fix db-dump Since changeset af47954c1015 we would die with: AttributeError: 'ServerMigrationHelper' object has no attribute 'repo'

[server/test] sorting vs dict vs python3