[BUGFIX] AppHelper.loadRecursively will expose instance properties to global context

[Seitk]

Given an example:

We have a model called ServiceClient

class A {
  constructor() {
    this.propA = '1';
  }
}

class B {
  constructor() {
    this.propB = '2';
  }
}

module.exports = {
  A: new A(),
  B: new B(),
}

In AppHelper after importDir the call of flat will expand properties of object instance and adding the value to global context.

With the example above, the global context will contain 2 variables

ServiceClient_A_propA=1
ServiceClient_B_propB=2