Add KotlinFeature for configuration settings?

[cowtowncoder]

(note: inspired by #439 work)

As things are, KotlinModule has a few configuration options, and at least 4 are boolean-valued (plus #439 would add one more, at least temporarily). Since they have to be passed separately, adding a new option requires more changes than is ideal, and technically also reduces cross-version compatibility (although constructors should not really be called from outside).

Most Jackson components offer Feature style on/off settings, in which we can have up to 31 options (or, if using long, 63 -- and of course with diff. backends even more) and make it much easier to add new options, only adding enum entries but no need to add new methods, constructors etc.
Implementation for int-backed variant -- which I think is sufficient for Kotlin module, with a smallish set of on/off things -- is done by implementing JacksonFeature. I don't deeply care if that is used or something else, but I think the general idea is good.
(note: the reason I chose not to use BitSet from JDK originally was because that is not immutable so copies were needed; any similar data struct is fine with me).

[dinomite]

Great idea. What's the timeline like for Jackson 2.13? I'm wondering whether to scope this for then or later.

[cowtowncoder]

I have been bit swamped at work lately, so we are not yet close to RC phase. I think that if all goes well, we might get first RC in early July? So there is quite a bit of time I think.
I think this would be great to have for 2.13.

[dinomite]

This is a great case for someone new to Jackson or to open source work to tackle. Other Jackson components provide a good model and the area where this work needs to happen is fairly contained & straightforward. I'm happy to give pointers and help someone get started on this.

[efenderbosch]

What should this look like in use?

KotlinModule()
    .enable(SingletonSupport)
    .disable(SomeEnabledByDefaultFeature)

[cowtowncoder]

I think use of Builder-style would be good (since Jackson 3.0 moves to that for ObjectMapper and TokenStreamFactory), but I defer to @dinomite here.

[efenderbosch]

So like this?

KotlinModule.Builder()
    .withReflectionCacheSize(1024)
    .enable(SingletonSupport)
    .disable(SomeEnabledByDefaultFeature)
    .build()

[cowtowncoder]

@efenderbosch exactly

[dinomite]

Complete!