Allow field defaults to be computed

[edalzell]

Use Case:

I have a custom Timezone dictionary and I'd like to have a default that's pulled from an addon's settings.

Best way IMO, would be to have a default: computed (like field visibility) and then a way to register a closure for that field. Something like Blueprint/Fieldset::default('blueprint', 'field', function () { ...});

The default should be selected and visible on a new entry.

[edalzell]

Brainstorming:

DX should be similar to computed fields:

Collection::default('articles', 'shares', function ($entry, $value) {
    return $yourValueHere;
});