Extract control flow analysis to separate module

Extract a service interface out of ControlFlowInformationProviderImpl
and register its implementation in two "leaf" modules: 'cli',
'idea-core'.

This improves parallel build, since a lot of modules depend on
'frontend' but only these two modules reference the implementation and
thus depend on the full CFA implementation now.

prepare/idea-plugin/build.gradle.kts

@@ -62,6 +62,7 @@ val projectsToShadow by extra(listOf(
         ":compiler:frontend",
         ":compiler:frontend.common",
         ":compiler:frontend.java",
+        ":compiler:frontend:cfg",
         ":idea",
         ":idea:idea-native",
         ":idea:idea-core",