[DEST-236][DEST-682][DEST-777][CC-4860] Facebook Pixel v2.8.0 (#143)

* Fix tests

* [DEST-682] Allow to set `content_type` from integration options

* [DEST-777] Add `content_type` to Checkout Started

* Refactor build payload for FB event

* [DEST-236] Add custom properties to Standard Events

* Version 2.8.0

Author: CarlosMecha

.eslintrc

@@ -13,7 +13,8 @@
     "no-restricted-syntax": "warn",
     "no-continue": "warn",
     "consistent-return": "warn",
-    "no-shadow": "warn"
+    "no-shadow": "warn",
+    "no-plusplus": "off"
   },
   "overrides": [
     {