Fix LDAP Extended Query example.

The old one was not valid LDAP filter syntax.
Improve Authentication Containers examples.

* The first example was wrong (cf. ldap_backed() in auth.inc which
  looks for a DC= part to determine a full DN.
* The second example now show the realtive DNs.
Don't gettext() the example strings.

They must not be translated.
Enhance interface gateway data entry descriptions
Enhance interface gateway data entry descriptions
Update rrd.inc

Add NTP graphing to RRD
Update system.inc

Add new NTPd functions
Update services_ntpd.php

Extended options for NTPd
Create services_ntpd_gps.php

Separate page to set GPS receiver pps sync
Create services_ntpd_pps.php

Separate page for other PPS sources config
Update status_ntpd.php

A bit more informative NTP status page...
Update status_rrd_graph.php

Add NTP graphing
Update status_rrd_graph_img.php

Add NTP graph drawing
Update status_rrd_graph_settings.php

Add NTP graph to settings
Create ntp_status.inc

NTP widget helper
Create ntp_status.widget.php

Dedicated widget which has a javascript clock showing the server time accurately, and based on NTP's running state displays information about sync source, GPS state etc. It refreshes contents every minute, without reloading the entire page.
Update ntp_status.widget.php

Updated errorneous paths. Sorry.
Update system.inc

Corrections made as requested
Update rrd.inc

corrected path
Dodgy-looking stuff in graph calculations

I noticed that the graphs in this post - https://forum.pfsense.org/index.php/topic,72794.0.html - had numbers for in-block and out-block that had similar numbers to in-pass and out-pass. That seemed hard to believe. Found these calculations that look wrong.