clean up server.js

[wunderbarr]

• clean up server.js
  0. By definition, REQUIRE_SIGN_IN should be a boolean variable. But currently it is string type, e.g. 'true', fix it and relevant code in config/globals.js
  1. acl rules on/off -> env variable and only be settable if sign in is on
  2. mergeSchema and additional scalar types into helper
  3. comment on bodyParser
  4. awaitify login
  5. delete join stuff
  6. awaitify export
  7. meta query functions into a module
  8. kill operator aliases
  9. indentation issue