Order of programatically registered extensions should consider class level annotations

[stevenschlansker]

We are implementing two companion extensions. Configuring them is complicated enough that we use the programmatic @RegisterExtension.

The extensions are usable separately, or together. When used together, one must always be initialized before the other.

Currently, seemingly the only way to do this is:

class Extension1 implements BeforeAllCallback { ... }
class Extension2 implements BeforeAllCallback { ... }

class TestCase {
    @RegisterExtension
    @Order(1)
    static Extension1 e1 = new Extension1();

    @RegisterExtension
    @Order(2)
    static Extension2 e2 = new Extension2();
}

We'd like to provide a sensible default so that users don't have to think about this:

@Order(1)
class Extension1 implements BeforeAllCallback { ... }
@Order(2)
class Extension2 implements BeforeAllCallback { ... }

class TestCase {
    @RegisterExtension
    static Extension1 e1 = new Extension1();

    @RegisterExtension
    static Extension2 e2 = new Extension2();
}

Right now this seems to not be possible. It looks like a straightforward improvement to ExtensionUtils.getOrder(Field) to consider first the field, then the field's type, then the default.

Did I miss some easier way to accomplish this? Thanks!