Switch to ldap3

[adorton-adobe]

python-ldap is a pain point for build management. The team that maintains it does not provide builds for win64 and building it from source on win64 is fairly complicated. We currently rely on an unofficial repository of win64 builds of many popular Python dependencies. Reliance on this source isn't a good idea for long term project sustainability. It also prevents us from supporting Python 3.7 because we're pegged to an older version of python-ldap that doesn't support 3.7. Upgrading that dependency will require extensive testing (which we'll need to do anyway if we switch to ldap3).

ldap3 is a mature, pure Python ldap client library that won't present any of the problems we have with python-ldap. It additionally has a nicer, more Pythonic interface and may make it easier to support certain features that customers have requested (such as StartTLS).

We should plan to migrate the ldap connector to use ldap3 and target that update to the 2.5 release.

[adorton-adobe]

This is merged so we can close this.