feat: Add main application views and structure

- Implemented CreateInstanceView for creating new instances.
- Added HostsView for managing SSH hosts with CRUD operations.
- Created InstancesView for displaying and managing instances.
- Developed LogsView for viewing operation logs.
- Introduced SecretsView for managing secrets associated with hosts.
- Established SettingsView for configuring application settings.
- Created MainWindow as the main application window with navigation.
- Added app manifest and configuration files for logging and settings.

OTSSignsOrchestrator.Desktop/Views/SecretsView.axaml

@@ -0,0 +1,37 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:vm="using:OTSSignsOrchestrator.Desktop.ViewModels"
+             x:Class="OTSSignsOrchestrator.Desktop.Views.SecretsView"
+             x:DataType="vm:SecretsViewModel">
+
+    <DockPanel>
+        <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Spacing="8" Margin="0,0,0,12">
+            <ComboBox ItemsSource="{Binding AvailableHosts}"
+                      SelectedItem="{Binding SelectedSshHost}"
+                      PlaceholderText="Select SSH Host..."
+                      Width="250">
+                <ComboBox.ItemTemplate>
+                    <DataTemplate>
+                        <TextBlock Text="{Binding Label}" />
+                    </DataTemplate>
+                </ComboBox.ItemTemplate>
+            </ComboBox>
+            <Button Content="Load Secrets" Command="{Binding LoadSecretsCommand}" />
+        </StackPanel>
+
+        <TextBlock DockPanel.Dock="Bottom" Text="{Binding StatusMessage}" Margin="0,8,0,0"
+                   FontSize="12" Foreground="#a6adc8" />
+
+        <DataGrid ItemsSource="{Binding Secrets}"
+                  AutoGenerateColumns="False"
+                  IsReadOnly="True"
+                  GridLinesVisibility="Horizontal"
+                  CanUserResizeColumns="True">
+            <DataGrid.Columns>
+                <DataGridTextColumn Header="ID" Binding="{Binding Id}" Width="200" />
+                <DataGridTextColumn Header="Name" Binding="{Binding Name}" Width="250" />
+                <DataGridTextColumn Header="Created" Binding="{Binding CreatedAt, StringFormat='{}{0:g}'}" Width="180" />
+            </DataGrid.Columns>
+        </DataGrid>
+    </DockPanel>
+</UserControl>