Move danger to bots directory

Summary:
No logic change here. Part of a plan to consolidate CI-only files amongst .circleci and bots/ directories.
Closes https://github.com/facebook/react-native/pull/17807

Differential Revision: D6865976

Pulled By: hramos

fbshipit-source-id: 48607a80dcf8cac1c3c033c18bf5d6dd4cd8e6bf

bots/package.json

@@ -0,0 +1,11 @@
+{
+  "private": true,
+  "scripts": {
+    "danger": "node ./node_modules/.bin/danger"
+  },
+  "devDependencies": {
+    "danger": "^2.1.6",
+    "lodash.includes": "^4.3.0",
+    "minimatch": "^3.0.4"
+  }
+}