Provide a new form component to simplify form authoring

When I tried to implement a logout form, this is what I ended up with:

```razor

Logout

```

It didn't make sense to use `EditForm` for this form because `EditForm` requires a model or an edit context, which I don't really need.

A couple of observations:
- I had to explicitly specify a form name, which is now required for all forms
- I had to manually add antiforgery support

In Razor Pages the form tag helper handles these concerns for you:

```

Logout

```

Should we provide a new framework component that makes authoring these sorts of forms easier?