JVM IR: remove dependency of 'backend.jvm' on 'psi2ir', 'ir.serialization.jvm'

Add a new module 'backend.jvm.entrypoint' which depends on psi2ir and
contains code that runs psi2ir + JVM IR backend with serialization
implementations.

Hopefully this will allow to compile these modules in parallel and
reduce the build time.

prepare/idea-plugin/build.gradle.kts

@@ -19,6 +19,7 @@ val projectsToShadow by extra(listOf(
         ":compiler:backend.common.jvm",
         ":compiler:backend-common",
         ":compiler:backend.jvm",
+        ":compiler:backend.jvm:backend.jvm.entrypoint",
         ":compiler:ir.backend.common",
         ":compiler:ir.serialization.jvm",
         ":compiler:ir.serialization.common",