refactor(date-picker): remove unused value and required bindings

Author: desig9stein

src/app/date-picker/date-picker.sample.html

@@ -6,10 +6,8 @@ <h6>Angular Date Picker</h6>
             formControlName="datePicker"
             [mode]="modeAngular"
             [type]="properties.type"
-            [value]="properties.value"
             [displayFormat]="properties.displayFormat"
             [inputFormat]="properties.inputFormat"
-            [required]="properties.required"
             [readOnly]="properties.readonly"
             [disabled]="properties.disabled"
             [placeholder]="properties.placeholder"