[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.
^build$
^dist$
\.egg-info$
^.tox$
^.cache$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$
\.old$
\.pybuild
cubicweb/server/test/data/slapd.conf
debian/python-cubicweb
debian/*.log
debian/*.substvars
debian/cubicweb-doc
debian/cubicweb
debian/files
syntax: regexp
.*/data.*/database/.*
.*/data/ldapdb/.*
.*/data/uicache/
.*/data/libpython/cubicweb_.*/i18n/.*\.po
^doc/html/
^doc/doctrees/
^doc/book/en/devweb/js_api/
^doc/_build
^doc/js_api/
test-results.xml