Error handling system added

Views/ErrorView.axaml

@@ -0,0 +1,44 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:vm="using:GazpromApp.ViewModels"
+        x:Name="Window"
+        mc:Ignorable="d" d:DesignWidth="400" d:DesignHeight="180"
+        Width="400" Height="180"
+        x:Class="GazpromApp.Views.ErrorView"
+        x:DataType="vm:ErrorViewModel"
+        Title="{Binding Title}"
+        Icon="/Assets/ic_fluent_error_circle_24_filled (1) (Custom).png"
+        WindowStartupLocation="CenterOwner"
+        Closing="Window_OnClosing"
+        Closed="Window_OnClosed">
+  <Design.DataContext>
+    <vm:ErrorViewModel/>
+  </Design.DataContext>
+  <Grid x:Name="Root" Margin="16"
+        ColumnDefinitions="50, *" RowDefinitions="50, *, Auto">
+    <Image Grid.Row="0" Grid.Column="0" 
+           IsVisible="{Binding IsErrorVisible}"
+           Source="avares://GazpromApp/Assets/ic_fluent_error_circle_24_filled (Custom).png"/>
+    <Image Grid.Row="0" Grid.Column="0"  
+           IsVisible="{Binding IsWarnVisible}"
+           Source="avares://GazpromApp/Assets/ic_fluent_warning_24_filled (Custom).png"/>
+    <Image Grid.Row="0" Grid.Column="0"  
+           IsVisible="{Binding IsInfoVisible}"
+           Source="avares://GazpromApp/Assets/ic_fluent_info_24_filled (Custom).png"/>
+    <Panel Grid.Row="0" Grid.Column="1" Grid.RowSpan="2">
+      <StackPanel Margin="8">
+        <TextBlock Text="{Binding Title}" FontSize="20" MaxLines="2" TextWrapping="Wrap"/>
+        <TextBlock Text="{Binding Message}" MaxLines="3" TextWrapping="Wrap"/>
+      </StackPanel>
+    </Panel>
+    <Panel Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="2">
+      <StackPanel Orientation="Horizontal" HorizontalAlignment="Right">
+        <Button Content="ОК" 
+                Command="{Binding OkCommand}"
+                CommandParameter="{Binding #Window}"/>
+      </StackPanel>
+    </Panel>
+  </Grid>
+</Window>