[EC-259] Added Account Switching to Share extension on iOS (#1971)

* EC-259 Added Account switching on share extension on iOS, also improved performance for this and exception handling

* EC-259 code formatting

* EC-259 Added account switching to Share extension Send view

* EC-259 Fixed navigation on share extension when a forms page is already presented

* EC-259 Fix send text UI update when going from the iOS extension

* EC-259 Improved DateTimeViewModel with helper property to easily setup date and time at the same time and applied on usage

src/iOS.ShareExtension/ExtensionNavigationController.cs

@@ -0,0 +1,27 @@
+// This file has been autogenerated from a class added in the UI designer.
+
+using System;
+using UIKit;
+
+namespace Bit.iOS.ShareExtension
+{
+    public partial class ExtensionNavigationController : UINavigationController
+	{
+		public ExtensionNavigationController (IntPtr handle) : base (handle)
+		{
+		}
+
+        public override UIViewController PopViewController(bool animated)
+        {
+            TopViewController?.Dispose();
+            return base.PopViewController(animated);
+
+        }
+
+        public override void DismissModalViewController(bool animated)
+        {
+            ModalViewController?.Dispose();
+            base.DismissModalViewController(animated);
+        }
+    }
+}