Added OpenSea API key to config

refs https://github.com/TryGhost/Team/issues/1237

We want to use an API key for OpenSea where possible so that we do not
run into rate limit issues.

core/server/api/canary/oembed.js

@@ -4,7 +4,11 @@ const externalRequest = require('../../lib/request-external');
 const OEmbed = require('../../services/oembed');
 const oembed = new OEmbed({config, externalRequest});
 const NFT = require('../../services/nft-oembed');
-const nft = new NFT();
+const nft = new NFT({
+    config: {
+        apiKey: config.get('opensea').privateReadOnlyApiKey
+    }
+});
 oembed.registerProvider(nft);
 
 module.exports = {

core/server/services/nft-oembed.js

@@ -35,8 +35,13 @@ class NFTOEmbedProvider {
         if (!match) {
             return null;
         }
+        const headers = {};
+        if (this.dependencies.config.apiKey) {
+            headers['X-API-KEY'] = this.dependencies.config.apiKey;
+        }
         const result = await externalRequest(`https://api.opensea.io/api/v1/asset/${transaction}/${asset}/?format=json`, {
-            json: true
+            json: true,
+            headers
         });
         return {
             version: '1.0',

core/shared/config/defaults.json

@@ -133,5 +133,8 @@
     "tenor": {
         "apiKey": null,
         "contentFilter": "off"
+    },
+    "opensea": {
+        "privateReadOnlyApiKey": null
     }
 }