Add FOV cone visualization to map screens; refactor geoMath utility for heading and cone calculations

Have FOV config as it's own thing so it's easier to change the size of the FOV triangle without having to change multiple parts of the maths for it.

Fov triangle needed because for some reason maps doesn't let us have our own fov ??

src/components/gameplay/PlayerMapView.js

@@ -1,6 +1,6 @@
 import React from 'react';
-import {StyleSheet, View} from 'react-native';
-import MapView, {Circle, Marker} from 'react-native-maps';
+import MapView, {Circle, Polygon} from 'react-native-maps';
+import {getFovCone} from '../../utils/geoMath';
 
 const PlayerMapView = ({ userLocation, visibleCache, heading }) => {
 //   Initialisation -------------
@@ -10,6 +10,10 @@ const PlayerMapView = ({ userLocation, visibleCache, heading }) => {
 
   if (!userLocation) return null;
 
+  const coneCoords = (heading !== null && heading !== undefined)
+    ? getFovCone(userLocation, heading)
+    : null;
+
   return (
     <MapView
       style={{flex: 1}}
@@ -32,35 +36,17 @@ const PlayerMapView = ({ userLocation, visibleCache, heading }) => {
           strokeColor="rgba(250, 204, 21, 0.90)"
         />
       ) : null}
-      {heading !== null && heading !== undefined && (
-        <Marker
-          coordinate={userLocation}
-          flat={true}
-          rotation={heading}
-          anchor={{x: 0.5, y: 1.0}}
-          tracksViewChanges={false}
-        >
-          <View style={styles.coneWrap}>
-            <View style={styles.cone}/>
-          </View>
-        </Marker>
+      {coneCoords && (
+        <Polygon
+          coordinates={coneCoords}
+          fillColor="rgba(66,133,244,0.28)"
+          strokeColor="rgba(66,133,244,0.50)"
+          strokeWidth={1}
+        />
       )}
     </MapView>
   );
 };
 
-const styles = StyleSheet.create({
-  coneWrap: {width: 22, height: 24, alignItems: 'center'},
-  cone: {
-    width: 0,
-    height: 0,
-    borderTopWidth: 24,
-    borderLeftWidth: 11,
-    borderRightWidth: 11,
-    borderTopColor: 'rgba(37,99,235,0.70)',
-    borderLeftColor: 'transparent',
-    borderRightColor: 'transparent',
-  },
-});
 
 export default PlayerMapView;