Add timing to LDAP logging to make identifying timeouts easier.

When timeouts (either the one configured by us, or one configured on the LDAP server) cause a connection to be closed, the logging does not make this obvious as we just see a generic TCP error such as in the following logs:

[ns_server:debug,2023-09-28T02:33:05.638-05:00,ns_1@xxx:<0.26791.3621>:ldap_util:with_connection:143]Connected to LDAP server: "<LDAP server address>" (port: 636, SSL: true)

<intermediate messages cut>

[ns_server:debug,2023-09-28T02:33:09.638-05:00,ns_1@xxx:<0.26791.3621>:ldap_util:with_simple_bind:199]Simple bind for DN "<LDAP DN>": {error,{gen_tcp_error,closed}} 

It would be helpful if the second message included the time elapsed since the first message was logged, in this case 4 seconds by comparing the timestamp. This will make it much easier to see patterns in the timing for connections being closed, which give good circumstantial evidence for us to conclude that timeouts are responsible (rather than other connectivity issues).