Added EF and DB to the core, crude demo in the UI

WinWARP.Core/Data/AppDbContext.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Microsoft.EntityFrameworkCore;
+using WinWARP.Core.Models.Entities;
+
+namespace WinWARP.Core.Data;
+
+public class AppDbContext : DbContext
+{
+    public DbSet<Subscription> Subscriptions => Set<Subscription>();
+
+    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
+    {
+
+    }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        modelBuilder.Entity<Subscription>()
+            .HasKey(s => s.Id);
+    }
+}