pgsql: ldapurl is supported with simple bind

ldapurl is supported with simple bind

The docs currently imply that ldapurl is for search+bind only, but
that's not true.  Rearrange the docs to cover this better.

Add a test ldapurl with simple bind.  This was previously allowed but
unexercised, and now that it's documented it'd be good to pin the
behavior.

Improve error when mixing LDAP bind modes.  The option names had gone
stale; replace them with a more general statement.

Author: Jacob Champion <jacob.champion@enterprisedb.com>
Discussion:
https://www.postgresql.org/message-id/flat/CAOYmi+nyg9gE0LeP=xQ3AgyQGR=5ZZMkVVbWd0uR8XQmg_dd5Q@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/f68d85bf69233ef842a08707bbd1204ef8216549

Modified Files
--------------
doc/src/sgml/client-auth.sgml | 23 ++++++++++++++++++++---
src/backend/libpq/hba.c       |  4 ++--
src/test/ldap/t/001_auth.pl   | 16 ++++++++++++++++
3 files changed, 38 insertions(+), 5 deletions(-)