Add jackson benchmarks

[jzbrooks]

Jackson still has quite a large user base, so it would be useful to have benchmarks to compare against code-generator serializers.

https://github.com/FasterXML/jackson-databind
https://github.com/FasterXML/jackson-module-kotlin

Add benchmarks for every combination of:

1. to/from json
2. string/buffer
3. jackson-databind/jackson-module-kotlin

[jzbrooks]

I was experimenting with some changes in a project I work on, so I'll draft an incomplete PR that does all this work but so far lacks an issue endorsement (per contribution guidelines) and I'll need to update recorded benchmarks if you'd like these benchmarks to be added to the repo.

[jzbrooks]

@ZacSweers, are you interested in this addition? I can close the issue/pr if not.