DBController refactoring (#1228)

* Moves transform to MongoTransform

- Adds ACL query injection in MongoTransform

* Removes adaptiveCollection from DatabaseController

- All collections manipulations are now handled by a DBController
- Adds optional flags to configure an unsafe databaseController for direct
  access
- Adds ability to configure RestWrite with multiple writes
- Moves some transfirmations to MongoTransform as they output specific code

* Renames Unsafe to WithoutValidation

spec/ParseGlobalConfig.spec.js

@@ -7,7 +7,7 @@ let Config = require('../src/Config');
 describe('a GlobalConfig', () => {
   beforeEach(done => {
     let config = new Config('test');
-    config.database.adaptiveCollection('_GlobalConfig')
+    config.database.adapter.adaptiveCollection('_GlobalConfig')
       .then(coll => coll.upsertOne({ '_id': 1 }, { $set: { params: { companies: ['US', 'DK'] } } }))
       .then(() => { done(); });
   });
@@ -43,6 +43,35 @@ describe('a GlobalConfig', () => {
     });
   });
 
+  it('properly handles delete op', (done) => {
+    request.put({
+      url    : 'http://localhost:8378/1/config',
+      json   : true,
+      body   : { params: { companies: {__op: 'Delete'}, foo: 'bar' } },
+      headers: {
+        'X-Parse-Application-Id': 'test',
+        'X-Parse-Master-Key'    : 'test'
+      }
+    }, (error, response, body) => {
+      expect(response.statusCode).toEqual(200);
+      expect(body.result).toEqual(true);
+      request.get({
+        url    : 'http://localhost:8378/1/config',
+        json   : true,
+        headers: {
+          'X-Parse-Application-Id': 'test',
+          'X-Parse-Master-Key'    : 'test'
+        }
+      }, (error, response, body) => {
+        expect(response.statusCode).toEqual(200);
+        expect(body.params.companies).toBeUndefined();
+        expect(body.params.foo).toBe('bar');
+        expect(Object.keys(body.params).length).toBe(1);
+        done();
+      });
+    });
+  });
+
   it('fail to update if master key is missing', (done) => {
     request.put({
       url    : 'http://localhost:8378/1/config',
@@ -61,7 +90,7 @@ describe('a GlobalConfig', () => {
 
   it('failed getting config when it is missing', (done) => {
     let config = new Config('test');
-    config.database.adaptiveCollection('_GlobalConfig')
+    config.database.adapter.adaptiveCollection('_GlobalConfig')
       .then(coll => coll.deleteOne({ '_id': 1 }))
       .then(() => {
         request.get({