Ldap authenticator

[dmgav]

Implementation of LDAP authenticator. The authenticator could be configured in .yml file as

authentication:
    providers:
        - provider: ldap_local 
          authenticator: tiled.authenticators:LDAPAuthenticator
          args:
              server_address: localhost
              server_port: 1389
              bind_dn_template: "cn={username},ou=users,dc=example,dc=org"
              use_tls: false
              use_ssl: false
    tiled_admins:
        - provider: ldap_local 
          id: user02

[dylanmcreynolds]

Let preface this comment by acknowledging this is the very first test_authenticators.py commit, so thanks for adding it!

Possibly for a later PR, but have you thought of mocking the ldap3 code? I have no experience mocking ldap, but there even seems to be some support in ldap3 https://ldap3.readthedocs.io/en/latest/mocking.html

[danielballan]

• I am grateful that this has unit tests, period. (More than I did with PAM, OIDC, SAML!)
• I agree with @dylanmcreynolds that this would be a good use for mocking.
• Given internal NSLS-II time pressures I think I'm in favor of refactoring to mocking in a separate PR.