Implementation of multi-sprites in mbgl-core (#1858)

Co-authored-by: Christophe Brasseur <christophe.brasseur@geolives.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Bart Louwers <bart.louwers@gmail.com>
Co-authored-by: Bart Louwers <bart@emeel.net>

metrics/integration/render-tests/sprites/array-default-only/style.json

@@ -0,0 +1,56 @@
+{
+  "version": 8,
+  "metadata": {
+    "test": {
+      "pixelRatio": 1,
+      "width": 128,
+      "height": 64
+    }
+  },
+  "center": [
+    0,
+    0
+  ],
+  "zoom": 0,
+  "sources": {
+    "geojson": {
+      "type": "geojson",
+      "data": {
+        "type": "FeatureCollection",
+        "features": [
+          {
+            "type": "Feature",
+            "properties": {},
+            "geometry": {
+              "type": "Point",
+              "coordinates": [25, 0]
+            }
+          },
+          {
+            "type": "Feature",
+            "properties": {},
+            "geometry": {
+              "type": "Point",
+              "coordinates": [-25, 0]
+            }
+          }
+        ]
+      }
+    }
+  },
+  "sprite": [{
+    "id": "default",
+    "url": "local://sprites/emerald"
+  }],
+  "layers": [
+    {
+      "id": "default",
+      "type": "symbol",
+      "source": "geojson",
+      "layout": {
+        "symbol-placement": "point",
+        "icon-image": "post_icon"
+      }
+    }
+  ]
+}

metrics/integration/render-tests/sprites/array-multiple/style.json

@@ -0,0 +1,79 @@
+{
+  "version": 8,
+  "metadata": {
+    "test": {
+      "pixelRatio": 1,
+      "width": 128,
+      "height": 64
+    }
+  },
+  "center": [
+    0,
+    0
+  ],
+  "zoom": 0,
+  "sources": {
+    "source-one": {
+      "type": "geojson",
+      "data": {
+        "type": "FeatureCollection",
+        "features": [
+          {
+            "type": "Feature",
+            "properties": {},
+            "geometry": {
+              "type": "Point",
+              "coordinates": [25, 0]
+            }
+          }
+        ]
+      }
+    },
+    "source-two": {
+      "type": "geojson",
+      "data": {
+        "type": "FeatureCollection",
+        "features": [
+          {
+            "type": "Feature",
+            "properties": {},
+            "geometry": {
+              "type": "Point",
+              "coordinates": [-25, 0]
+            }
+          }
+        ]
+      }
+    }
+  },
+  "sprite": [
+    {
+      "id": "default",
+      "url": "local://sprites/emerald"
+    },
+    {
+      "id": "sprite",
+      "url": "local://sprites/sprite"
+    }
+  ],
+  "layers": [
+    {
+      "id": "default-sprite-features",
+      "type": "symbol",
+      "source": "source-one",
+      "layout": {
+        "symbol-placement": "point",
+        "icon-image": "post_icon"
+      }
+    },
+    {
+      "id": "sprite-sprite-features",
+      "type": "symbol",
+      "source": "source-two",
+      "layout": {
+        "symbol-placement": "point",
+        "icon-image": "sprite:night-lighthouse-12"
+      }
+    }
+  ]
+}