AP_Camera: stop libraries including AP_Logger.h in .h files

AP_Logger.h is a nexus of includes; while this is being improved over
time, there's no reason for the library headers to include AP_Logger.h
as the logger itself is access by singleton and the structures are in
LogStructure.h

This necessitated moving The PID_Info structure out of AP_Logger's
namespace.  This cleans up a pretty nasty bit - that structure is
definitely not simply used for logging, but also used to pass pid
information around to controllers!

There are a lot of patches in here because AP_Logger.h, acting as a
nexus, was providing transitive header file inclusion in many (some
unlikely!) places.

libraries/AP_Camera/AP_Camera.h

@@ -2,9 +2,10 @@
 /// @brief	Photo or video camera manager, with EEPROM-backed storage of constants.
 #pragma once
 
+#include <AP_Common/Location.h>
+#include <AP_Logger/LogStructure.h>
 #include <AP_Param/AP_Param.h>
 #include <GCS_MAVLink/GCS_MAVLink.h>
-#include <AP_Logger/AP_Logger.h>
 
 #define AP_CAMERA_TRIGGER_DEFAULT_DURATION  10      // default duration servo or relay is held open in 10ths of a second (i.e. 10 = 1 second)