[entities] Restore dc_ methods instead of __getattr__ proxy In 8de62610cea2, a __getattr__ proxy was introduced to handle compatibility with dc_* methods being called on entity instances instead of through the IDublinCore adapter. Unfortunately, __getattr__ does not play well with super() and since the latter is often used by, we here restore all dc_ methods with an explicit proxy to the adapter. More verbose but should work. Closes #17103999.

[bdist_wheel]
universal = 1

[check-manifest]
ignore =
  debian
  debian/*
  cubicweb.spec
  __pkginfo__.py