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/Routers/FilesRouter.js

@@ -34,7 +34,7 @@ export class FilesRouter {
   }
 
   getHandler(req, res) {
-    const config = new Config(req.params.appId);
+    const config = Config.get(req.params.appId);
     const filesController = config.filesController;
     const filename = req.params.filename;
     const contentType = mime.lookup(filename);

src/Routers/PublicAPIRouter.js

@@ -13,7 +13,7 @@ export class PublicAPIRouter extends PromiseRouter {
   verifyEmail(req) {
     const { token, username } = req.query;
     const appId = req.params.appId;
-    const config = new Config(appId);
+    const config = Config.get(appId);
 
     if (!config.publicServerURL) {
       return this.missingPublicServerURL();
@@ -38,7 +38,7 @@ export class PublicAPIRouter extends PromiseRouter {
   resendVerificationEmail(req) {
     const username = req.body.username;
     const appId = req.params.appId;
-    const config = new Config(appId);
+    const config = Config.get(appId);
 
     if (!config.publicServerURL) {
       return this.missingPublicServerURL();
@@ -65,7 +65,7 @@ export class PublicAPIRouter extends PromiseRouter {
 
   changePassword(req) {
     return new Promise((resolve, reject) => {
-      const config = new Config(req.query.id);
+      const config = Config.get(req.query.id);
       if (!config.publicServerURL) {
         return resolve({
           status: 404,
@@ -172,7 +172,7 @@ export class PublicAPIRouter extends PromiseRouter {
   }
 
   setConfig(req) {
-    req.config = new Config(req.params.appId);
+    req.config = Config.get(req.params.appId);
     return Promise.resolve();
   }