Send feature for mobile (#1256)

* Send feature for mobile

* added fallback for KdfIterations

* additional property exclusions for tests

* support encryptedFileData as byte array comparison in SendServiceTests

* formatting

* requested changes

* additional changes

* change position of send service registration to match declaration order

src/Android/Renderers/ExtendedDatePickerRenderer.cs

@@ -0,0 +1,50 @@
+using System.ComponentModel;
+using Android.Content;
+using Android.Views;
+using Bit.App.Controls;
+using Bit.Droid.Renderers;
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.Android;
+
+[assembly: ExportRenderer(typeof(ExtendedDatePicker), typeof(ExtendedDatePickerRenderer))]
+namespace Bit.Droid.Renderers
+{
+    public class ExtendedDatePickerRenderer : DatePickerRenderer
+    {
+        public ExtendedDatePickerRenderer(Context context)
+            : base(context) { }
+
+        protected override void OnElementChanged(ElementChangedEventArgs<DatePicker> e)
+        {
+            base.OnElementChanged(e);
+            if (Control != null && Element is ExtendedDatePicker element)
+            {
+                // center text
+                Control.Gravity = GravityFlags.CenterHorizontal;
+
+                // use placeholder until NullableDate set 
+                if (!element.NullableDate.HasValue)
+                {
+                    Control.Text = element.PlaceHolder;
+                }
+            }
+        }
+
+        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == DatePicker.DateProperty.PropertyName ||
+                e.PropertyName == DatePicker.FormatProperty.PropertyName)
+            {
+                if (Control != null && Element is ExtendedDatePicker element)
+                {
+                    if (Element.Format == element.PlaceHolder)
+                    {
+                        Control.Text = element.PlaceHolder;
+                        return;
+                    }
+                }
+            }
+            base.OnElementPropertyChanged(sender, e);
+        }
+    }
+}