Basic Doctor UI

Summary:
- Basic Doctor UI showing issues with installation
- Run healthchecks in background on startup and show warning message if something is wrong

Reviewed By: jknoxville

Differential Revision: D18502599

fbshipit-source-id: 194939a080ba7412ed3293d95c533bfad7031d3b

yarn.lock

@@ -3444,6 +3444,11 @@ envify@^4.0.0:
     esprima "^4.0.0"
     through "~2.3.4"
 
+envinfo@^7.4.0:
+  version "7.4.0"
+  resolved "https://registry.yarnpkg.com/envinfo/-/envinfo-7.4.0.tgz#bef4ece9e717423aaf0c3584651430b735ad6630"
+  integrity sha512-FdDfnWnCVjxTTpWE3d6Jgh5JDIA3Cw7LCgpM/pI7kK1ORkjaqI2r6NqQ+ln2j0dfpgxY00AWieSvtkiZQKIItA==
+
 err-code@^1.0.0:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/err-code/-/err-code-1.1.2.tgz#06e0116d3028f6aef4806849eb0ea6a748ae6960"
@@ -4115,6 +4120,13 @@ flatted@^2.0.0:
   resolved "https://registry.yarnpkg.com/flatted/-/flatted-2.0.1.tgz#69e57caa8f0eacbc281d2e2cb458d46fdb449e08"
   integrity sha512-a1hQMktqW9Nmqr5aktAux3JMNqaucxGcjtjWnZLHX7yyPCmlSV3M54nGYbqT8K+0GhF3NBgmJCc3ma+WOgX8Jg==
 
+flipper-doctor@^0.2.0:
+  version "0.2.0"
+  resolved "https://registry.yarnpkg.com/flipper-doctor/-/flipper-doctor-0.2.0.tgz#b0b1b51f3e6b99cf82eefe68098b74f75455e9d4"
+  integrity sha512-OQ+L4bm6OEcVGmmeQVwWJcPx6y6letE9BV+vkT2pS49jk2q1q++aJ+Z+aH7P0f/VfXpGYc3JaNUhMFie0A6LVQ==
+  dependencies:
+    envinfo "^7.4.0"
+
 flow-bin@0.112.0:
   version "0.112.0"
   resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.112.0.tgz#6a21c31937c4a2f23a750056a364c598a95ea216"