feat: Implement Database Service and ViewModels for Messages and Support Requests

- Added DatabaseService to handle database operations for messages and support requests.
- Created IDatabaseService interface to define the contract for database operations.
- Developed ViewModels for Dashboard, Messages, and Support pages to manage data and commands.
- Implemented XAML views for Dashboard, Messages, and Support, including data binding and UI elements.
- Created SQL script for setting up the database schema and inserting test data.

TravelMateAdmin/Models/Message.cs

@@ -0,0 +1,16 @@
+namespace TravelMateAdmin.Models;
+
+public class Message
+{
+    public int Id { get; set; }
+    public string Nom { get; set; } = string.Empty;
+    public string Prenom { get; set; } = string.Empty;
+    public string Email { get; set; } = string.Empty;
+    public string MessageText { get; set; } = string.Empty;
+    public bool Done { get; set; }
+    public DateTime CreatedAt { get; set; }
+
+    public string FullName => $"{Prenom} {Nom}";
+    public string StatusText => Done ? "Traité" : "En attente";
+    public string CreatedAtFormatted => CreatedAt.ToString("dd/MM/yyyy HH:mm");
+}

TravelMateAdmin/Models/SupportRequest.cs

@@ -0,0 +1,17 @@
+namespace TravelMateAdmin.Models;
+
+public class SupportRequest
+{
+    public int Id { get; set; }
+    public string Nom { get; set; } = string.Empty;
+    public string Prenom { get; set; } = string.Empty;
+    public string AccountEmail { get; set; } = string.Empty;
+    public string ContactEmail { get; set; } = string.Empty;
+    public string MessageText { get; set; } = string.Empty;
+    public bool Done { get; set; }
+    public DateTime CreatedAt { get; set; }
+
+    public string FullName => $"{Prenom} {Nom}";
+    public string StatusText => Done ? "Traité" : "En attente";
+    public string CreatedAtFormatted => CreatedAt.ToString("dd/MM/yyyy HH:mm");
+}