WebUI: Added placeholder help text and image for Debugging tab

docs/html/config_tvhlog.html

@@ -0,0 +1,28 @@
+<div class="hts-doc-text">
+
+ <img src="docresources/configtvhlog.png"></img>
+
+ <p>This tab is used to configure various debugging options in tvheadend.</p>
+
+ <p>Configuration options:</p>
+
+ <dl>
+
+  <dt>Debug log path</dt>
+  <dd></dd>
+
+  <dt>Debug to syslog</dt>
+  <dd></dd>
+
+  <dt>Debug trace (low-level stuff)</dt>
+  <dd></dd>
+
+  <dt>Debug subsystems</dt>
+  <dd></dd>
+
+  <dt>Trace subsystems</dt>
+  <dd></dd>
+
+ </dl>
+ Changes to any of these settings must be confirmed by pressing the 'Save configuration' button before taking effect.
+</div>