[repository] Drop the entities.extid column and associated cache This was not necessary anymore with promoted usage of the new data import API. Turn repository's _type_extid_cache to _type_cache with only the entity's type as key. This introduces an backward incompatible change: entity_metas dict doesn't contains anymore the extid key, but it doesn't seem used at all anywhere, so this sounds acceptable. Closes #15538317

.. _auth_module:

:mod:`cubicweb.pyramid.auth`
----------------------------

.. automodule:: cubicweb.pyramid.auth

    .. autofunction:: includeme

    .. autoclass:: UpdateLoginTimeAuthenticationPolicy
        :show-inheritance:
        :members: