- Split root project into `kyoJVM` and `kyoJS`. The JVM project is
selected by default, this way the regular development cycle is faster
but there's the downside that we might not catch issues in JS before CI.
It seems a reasonable tradeoff since it's possible to run the tests
manually by selecting the `kyoJS` project.
- Avoid the dependency on `kyo-core` tests in other modules. All other
modules end up stuck waiting for the core tests to compile because of
the dependency. I had to duplicate some of the code in `KyoTest` into
the other modules to achieve that.
- Move `scalafmt` from the build to a commit hook.
- Remove `-Wunused:all` compiler option. It significantly increases the
compilation times for tests. We can attempt to add it back once we're on
Scala 3.5, which seems to [improve build
times](#342 (comment))
with the option enabled.

Results with a cold JVM:

**Main**
```
$ sbt ";clean;compile"
[success] Total time: 24 s, completed May 30, 2024, 1:58:13 PM
$ sbt ";clean;test:compile"
[success] Total time: 58 s, completed May 30, 2024, 1:59:58 PM
$ sbt ";clean;test"
[success] Total time: 88 s (01:28), completed May 30, 2024, 2:01:45 PM
```

**This PR (default `kyoJVM` only)**
```
$ sbt ";clean;compile"
[success] Total time: 14 s, completed May 30, 2024, 1:54:29 PM
$ sbt ";clean;test:compile"
[success] Total time: 27 s, completed May 30, 2024, 1:55:51 PM
$ sbt ";clean;test"
[success] Total time: 39 s, completed May 30, 2024, 1:56:59 PM
```

I won't close #342 since there's
always opportunity to optimize the build.