Add ReplayStudio as submodule instead of JitPack

Because JitPack breaks Gradle variants so we get the Java 17 jar even
when we use the Java 8 variant.

This works for building via Gradle. However it does not work for usage
from IntelliJ, where you must currently publishToMavenLocal ReplayStudio
and then depend on that version. Still looking for a better solution
there.

settings.gradle.kts

@@ -74,6 +74,8 @@ val replayModVersions = listOf(
 
 rootProject.buildFileName = "root.gradle.kts"
 
+includeBuild("ReplayStudio")
+
 include(":jGui")
 project(":jGui").apply {
     projectDir = file("jGui")