[entity] Reimplement and deprecate entity.cw_metainformation
It shouldn't rely anymore on cnx.entity_metas which is itself deprecated, and
the cw_metainformation API is similarly not needed anymore, access directly to
cwuri / cw_source if needed.
Related to #15538288
from yams.buildobjs import ComputedRelation, EntityType, RelationDefinition
from cubicweb.schema import RRQLExpression
class Subject(EntityType):
pass
class Object(EntityType):
pass
class relation(RelationDefinition):
subject = 'Subject'
object = 'Object'
class computed(ComputedRelation):
rule = 'S relation O'
__permissions__ = {'read': (RRQLExpression('S is ET'),)}