[ldapfeed] make code compatible with ldap3>=2 * Some constants have been renamed. * Directly bind when data-cnx-dn/data-cnx-password are provided, some servers, including ours require this. * Use raise_exceptions=True to avoid ignored ldap errors * raise in case of failed anonymous bind * do not search for "dn" attribute because this raise an "invalid attribute" with new ldap3 versions * Password is now returned as bytes, so no longer need to encode them before crypt. * modification_date is now returned as a datetime object Co-Authored-By: Philippe Pepiot <philippe.pepiot@logilab.fr> Closes #16073071

### Requirements for tests in various cubicweb/**/test directories. ###

## shared by several test folders
cubicweb-card == 0.5.8
docutils
Twisted < 16.0.0
webtest

## cubicweb/test
Pygments
pycrypto
mock
#fyzz XXX pip install fails
cubicweb-file == 1.18.0
cubicweb-localperms == 0.3.2
cubicweb-tag == 1.8.3

## cubicweb/devtools/test
flake8

## cubicweb/hooks/test
psycopg2-binary

## cubicweb/pyramid/test
pyramid >= 1.5.0
waitress >= 0.8.9
wsgicors >= 0.3
pyramid_multiauth
repoze.lru

## cubicweb/sobject/test
cubicweb-comment == 1.12.2