First-class slf4j support

**Is your feature request related to a problem? Please describe.**
Its not clear how to configure kryo to use slf4j.

I see this
https://github.com/EsotericSoftware/kryo/issues/118

With this dead link:
https://code.google.com/archive/p/minlog/#Output_customization

Then this
https://github.com/jdanbrown/minlog-slf4j

And
https://github.com/dorkbox/MinLog-SLF4J

Depends on:
https://github.com/dorkbox/Updates

The only thing I care about logging is it must all go through slf4j.

**Describe the solution you'd like**
Clear instructions on the kryo page how to configure for slf4j.

**Describe alternatives you've considered**
The author should maintain an slf4j drop-in replacement for minlog and not defer this to community.
Now I have twice the risk and extra justification to my superiors for using kryo.

It doesn't matter how simple minlog implementation is, its always going to be more complex than just using the existing logging.