Retrieve multiple documents that are not neccesarily members or children

[MiguelAraCo]

Implement the following method signature in QueryableDocumentTrait::$get:

$get<T extends object>( uris: string[], queryBuilderFn: (queryBuilder: QueryDocumentBuilder) => QueryDocumentBuilder): Promise<Array<T & Document>>;
$get<T extends object>( uris: string[], requestOptions?: GETOptions, queryBuilderFn?: (queryBuilder: QueryDocumentBuilder) => QueryDocumentBuilder): Promise<Array<T & Document>>;