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

spec/EmailVerificationToken.spec.js

@@ -242,7 +242,7 @@ describe("Email Verification Token Expiration: ", () => {
         return user.signUp();
       })
       .then(() => {
-        const config = new Config('test');
+        const config = Config.get('test');
         return config.database.find('_User', {username: 'sets_email_verify_token_expires_at'});
       })
       .then(results => {
@@ -289,7 +289,7 @@ describe("Email Verification Token Expiration: ", () => {
           followRedirect: false,
         }, (error, response) => {
           expect(response.statusCode).toEqual(302);
-          const config = new Config('test');
+          const config = Config.get('test');
           return config.database.find('_User', {username: 'unsets_email_verify_token_expires_at'}).then((results) => {
             expect(results.length).toBe(1);
             return results[0];
@@ -448,7 +448,7 @@ describe("Email Verification Token Expiration: ", () => {
         return user.signUp();
       })
       .then(() => {
-        const config = new Config('test');
+        const config = Config.get('test');
         return config.database.find('_User', {username: 'newEmailVerifyTokenOnEmailReset'}).then((results) => {
           return results[0];
         });
@@ -465,7 +465,7 @@ describe("Email Verification Token Expiration: ", () => {
         });
       })
       .then(() => {
-        const config = new Config('test');
+        const config = Config.get('test');
         return config.database.find('_User', {username: 'newEmailVerifyTokenOnEmailReset'}).then((results) => {
           return results[0];
         });