Misc fixes 2 (#15190)

* Fix error when missing poller data

* Apparently impossible to detect regex without error, so require regex always.  Update docs.

* Apparently this adva code is garbage :D

* Missing count sensor type

* Processor handle missing input

* Handle missing ifName a little better

* Yep, ports module is a dumpster fire.  Attempt to clean up some.

* apparently os yaml trying to replace on non-existent fields

* Might as well define all sensor type units

* revert previous fix, real issue was vlans module does not have polling.

LibreNMS/OS/Traits/YamlOSDiscovery.php

@@ -164,11 +164,8 @@ trait YamlOSDiscovery
                     $replacement = $replacements[1];
                 }
 
-                // check for regex
-                if (preg_match($search, $device->$field)) {
+                if (isset($device->$field)) {
                     $device->$field = preg_replace($search, $replacement, $device->$field);
-                } else {
-                    $device->$field = str_replace($search, $replacement, $device->$field);
                 }
             }
         }