Feat/filter complex object

[ghiscoding]

In certain cases, our dataset might contain properties that are complex objects. This PR adds the possibility to filter correctly these complex objects.

For example, let say that we have this dataset

const dataset = [
 { item: 'HP Desktop', buyer: { id: 1234, address: { street: '123 belleville', zip: 123456 }},
 { item: 'Lenovo Mouse', buyer: { id: 456, address: { street: '456 hollywood blvd', zip: 789123 }}
];

We can now filter the zip code from the buyer's address using this filter:

this.columnDefinitions = [
  {
    // when the "field" string includes the dot "." notation, the library will consider this to be a complex object and Filter accordingly
    // so this Field, tells us the child value is "zip" which is under the parent tree "buyer"
    id: 'street', name: 'ZIP', field: 'buyer.address.zip',
    filterable: true,
    filter: {
      model: Filters.compoundInput
    },
   // ...
];