In-app vault export support (#729)

* First pass at vault export UI

* Password validation via cryptoService

* Export service framework

* support for constructing json export data

* Support for constructing csv export data

* Cleanup and simplification

* Completion of vault export feature

* Formatting and simplification

* Use dialog instead of toast for invalid master password entry

src/Core/Models/Export/LoginUri.cs

@@ -0,0 +1,31 @@
+using Bit.Core.Enums;
+using Bit.Core.Models.View;
+
+namespace Bit.Core.Models.Export
+{
+    public class LoginUri
+    {
+        public LoginUri() { }
+
+        public LoginUri(LoginUriView obj)
+        {
+            Match = obj.Match;
+            Uri = obj.Uri;
+        }
+
+        public UriMatchType? Match { get; set; }
+        public string Uri { get; set; }
+
+        public static LoginUriView ToView(LoginUri req, LoginUriView view = null)
+        {
+            if(view == null)
+            {
+                view = new LoginUriView();
+            }
+
+            view.Match = req.Match;
+            view.Uri = req.Uri;
+            return view;
+        }
+    }
+}