Add a hook for modifying the ldapbind password
The hook can be installed by a shared_preload library.
A similar mechanism could be used for radius paswords, for example, and
the type name auth_password_hook_typ has been shosen with that in mind.
John Naylor and Andrew Dunstan
Discussion: https://postgr.es/m/
469b06ed-69de-ba59-c13a-
91d2372e52a9@dunslane.net