Adding full DI navigation example for testing purposes.

- adding internal private field into FormBase class
- adding Extension methods into DependencyInjection namespace for use
- adding 2 NavigateTo extension methods for DI using ServiceProvider
- adding example project
- adding to readme as example

Examples/DependencyInjection/Database/BotDbContext.cs

@@ -0,0 +1,12 @@
+using Microsoft.EntityFrameworkCore;
+
+namespace DependencyInjection.Database;
+
+public class BotDbContext : DbContext
+{
+    public BotDbContext(DbContextOptions options) : base(options)
+    {
+    }
+
+    public DbSet<User> Users { get; set; }
+}

Examples/DependencyInjection/Database/User.cs

@@ -0,0 +1,7 @@
+namespace DependencyInjection.Database;
+
+public class User
+{
+    public long Id { get; set; }
+    public string LastMessage { get; set; }
+}