feat(backend-github): GitHub GraphQL API support (#2456)

* add GitHub GraphQL api initial support

* support mutiple backends for e2e tests - initial commit

* add github backend e2e test (currently skipped), fix bugs per tests

* refactor e2e tests, add fork workflow tests, support fork workflow in GraphQL api

* remove log message that might contain authentication token

* return empty error when commit is not found when using GraphQL (align with base class)

* disable github backend tests

* fix bugs introduced after rebase of GraphQL and OpenAuthoring features

* test: update tests per openAuthoring changes, split tests into multiple files

* fix: pass in headers for pagination requests, avoid async iterator as it requires a polyfill on old browsers

* test(e2e): disable github backend tests

package.json

@@ -72,6 +72,7 @@
     "@babel/plugin-proposal-object-rest-spread": "^7.3.4",
     "@babel/preset-env": "^7.3.4",
     "@babel/preset-react": "^7.0.0",
+    "@octokit/rest": "^16.28.7",
     "all-contributors-cli": "^6.0.0",
     "babel-core": "^7.0.0-bridge.0",
     "babel-eslint": "^10.0.1",
@@ -89,17 +90,21 @@
     "copy-webpack-plugin": "^5.0.1",
     "cross-env": "^5.2.0",
     "css-loader": "^3.0.0",
-    "cypress": "^3.1.5",
+    "cypress": "^3.4.1",
     "dom-testing-library": "^4.0.0",
+    "dotenv": "^8.0.0",
     "eslint": "^5.15.1",
+    "eslint-plugin-cypress": "^2.6.0",
     "eslint-plugin-emotion": "^10.0.7",
     "eslint-plugin-react": "^7.12.4",
     "friendly-errors-webpack-plugin": "^1.7.0",
+    "fs-extra": "^8.1.0",
     "http-server": "^0.11.1",
     "jest": "^24.5.0",
     "jest-cli": "^24.5.0",
     "jest-dom": "^3.1.3",
     "jest-emotion": "^10.0.9",
+    "js-yaml": "^3.13.1",
     "ncp": "^2.0.0",
     "nock": "^10.0.4",
     "node-fetch": "^2.3.0",
@@ -108,6 +113,7 @@
     "react-test-renderer": "^16.8.4",
     "react-testing-library": "^7.0.0",
     "rimraf": "^2.6.3",
+    "simple-git": "^1.124.0",
     "start-server-and-test": "^1.7.11",
     "stylelint": "^9.10.1",
     "stylelint-config-recommended": "^2.1.0",