CSRF protection implementation in Oxpecker

[Lanayx]

• Enabled by default for POST, PUT, PATCH requests if Antiforgery is also enabled (similar to MiminalApi)
• AntiforgeryValidationException is thrown on .BindForm (similar to MinimalApi's implementation)
• User can disable it using .DisableAntiforgery on endpoint
• User can add custom middleware to fail earlier if needed
• User can add CSRF on GET manually by using _.WithMetadata(RequireAntiforgeryTokenAttribute()) on endpoint
• User should use ctx.GetAntiforgeryInput() to add hidden antiforgery input to the form.

Now as there are three different exceptions that Oxpecker throws, I've added default error and not found handlers to use:

app.UseRouting()
    .Use(DefaultHandlers.errorHandler)
    .UseOxpecker(endpoints)
    .Run(DefaultHandlers.notFoundHandler)

[Thorium]

LGTM