Adding Configurator support for the Camera Angle Reference OSD feature

This is an OSD visual reference for current camera angle (open to name changes) intended to be used with a single axis tilt gimbal, like those shown on medlindrone.com

For 'Camera Angle Reference' there are five new cli parameters:
-osd_car_pos (osd element position)
-osd_car_channel (channel controlling the gimbal/car)
-osd_car_scale (scale for adjusting vertical scale/sensitivity)
-osd_car_width (width for adjusting witdh between dots)
-osd_car_dots (number of dots on each side)

For 'Camera Angle Reference Sidebar' there are seven new cli parameters:
-osd_car_sbar_pos; (osd element position)
-osd_car_sbar_scale; (scale for adjusting vertical scale)
-osd_car_sbar_low; (angle 1/5)
-osd_car_sbar_mid_low; (angle 2/5)
-osd_car_sbar_mid; (angle 3/5)
-osd_car_sbar_mid_high; (angle 4/5)
-osd_car_sbar_high; (angle 5/5)

locales/en/messages.json

@@ -5290,6 +5290,20 @@
     "osdDescElementHorizonSidebars": {
         "message": "Sidebars around artificial horizon indicator"
     },
+    "osdTextElementCameraAngleReference": {
+        "message": "Camera Angle Reference",
+        "description": "One of the elements of the OSD"
+    },
+    "osdDescElementCameraAngleReference": {
+        "message": "Camera angle reference for flying with FPV tilt gimbal"
+    },
+    "osdTextElementCameraAngleReferenceSidebar": {
+        "message": "Camera Angle Reference Sidebar",
+        "description": "One of the elements of the OSD"
+    },
+    "osdDescElementCameraAngleReferenceSidebar": {
+        "message": "Sidebar for Camera angle reference"
+    },
     "osdTextElementCurrentDraw": {
         "message": "Battery current draw",
         "description": "One of the elements of the OSD"

src/js/tabs/osd.js

@@ -1536,6 +1536,24 @@ OSD.loadDisplayFields = function() {
             positionable: true,
             preview: '1:23.456',
         },
+        CAM_ANGLE_REFERENCE: {
+            name: 'CAM_ANGLE_REFERENCE',
+            text: 'osdTextElementCameraAngleReference',
+            desc: 'osdDescElementCameraAngleReference',
+            defaultPosition: -1,
+            draw_order: 555,
+            positionable: true,
+            preview: '***CAR***',
+        },
+        CAM_ANGLE_REFERENCE_SBAR: {
+            name: 'CAM_ANGLE_REFERENCE_SBAR',
+            text: 'osdTextElementCameraAngleReferenceSidebar',
+            desc: 'osdDescElementCameraAngleReferenceSidebar',
+            defaultPosition: -1,
+            draw_order: 560,
+            positionable: true,
+            preview: '***SBR***||',
+        },
     };
 };
 
@@ -1970,6 +1988,8 @@ OSD.chooseFields = function() {
             F.GPS_LAP_TIME_CURRENT,
             F.GPS_LAP_TIME_PREVIOUS,
             F.GPS_LAP_TIME_BEST3,
+            F.CAM_ANGLE_REFERENCE,
+            F.CAM_ANGLE_REFERENCE_SBAR,
         ]);
     }