[ACHYDRA-1041] Add credentials for ldap service

[goldsmithb]

Jira Ticket

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This change adds a config/cul_ldap.yml file with the credentials for csa2151 service account which enables us to query the cul ldap server without raising an auth error (see here).

It also points to the branch of the cul-ldap gem that does not throw an error when the response from the LDAP server is nil.

N.B.: config/cul_ldap.yml has been created on dev, test, and prod:

shared:
    auth:
      method: simple
      username: "uni=csa2151,ou=People,o=Columbia University,c=US"  # Distinguished Name (dn)
      password: PASSWORD

[JackBlackLight]

@goldsmithb, I'm wondering if there is anything preventing the better-error-handling branch from being merged into cul-ldap master?

[goldsmithb]

I think it is ready to be merged in, what do you think @elohanlon? He made the changes to the gem.
In the mean time I'll make a jira ticket and a PR for that branch on cul-ldap so we can coordinate releasing a new version.

[JackBlackLight]

@goldsmithb, everything looks good - approving now, but if we can merge after the better_error_handling changes are in cul-ldap main that would be ideal.

[goldsmithb]

@goldsmithb, everything looks good - approving now, but if we can merge after the better_error_handling changes are in cul-ldap main that would be ideal.

Great, thanks Jack!
Eric and I finished up those changes on cul-ldap gem today, so that won't be a problem