Refactors configuration management (#4271)

* Adds flow types / Configuration interfaces

* Lets call it options

* Use a single interface to generate the configurations

* Translates options to definitions only if comments are set

* improves logic

* Moves objects around

* Fixes issue affecting logging of circular objects

* fixes undefined env

* Moves all defaults to defaults

* Adds back CLI defaults

* Restored defaults in commander.js

* Merge provided defaults and platform defaults

* Addresses visual nits

* Improves Config.js code

* Adds ability to pass the default value in trailing comments

* Load platform defaults from the definitions file

* proper default values on various options

* Adds ParseServer.start and server.start(options) as quick startup methods

* Moves creating liveQueryServer http into ParseServer.js

* removes dead code

* Adds tests to guarantee we can start a LQ Server from main module

* Fixes incorrect code regading liveQuery init port

* Start a http server for LQ if port is specified

* ensure we dont fail if config.port is not set

* Specify port

* ignore other path skipped in tests

* Adds test for custom middleware setting

* Refactors new Config into Config.get

- Hides AppCache from ParseServer.js, use Config.put which validates

* Extracts controller creation into Controllers/index.js

- This makes the ParseServer init way simpler

* Move serverURL inference into ParseServer

* review nits

src/cli/utils/commander.js

@@ -20,13 +20,6 @@ Command.prototype.loadDefinitions = function(definitions) {
     return program.option(`--${opt} [${opt}]`);
   }, this);
 
-  _defaults = Object.keys(definitions).reduce((defs, opt) => {
-    if(_definitions[opt].default) {
-      defs[opt] = _definitions[opt].default;
-    }
-    return defs;
-  }, {});
-
   _reverseDefinitions = Object.keys(definitions).reduce((object, key) => {
     let value = definitions[key];
     if (typeof value == "object") {
@@ -38,6 +31,13 @@ Command.prototype.loadDefinitions = function(definitions) {
     return object;
   }, {});
 
+  _defaults = Object.keys(definitions).reduce((defs, opt) => {
+    if(_definitions[opt].default) {
+      defs[opt] = _definitions[opt].default;
+    }
+    return defs;
+  }, {});
+
   /* istanbul ignore next */
   this.on('--help', function(){
     console.log('  Configure From Environment:');