Change kotlinx- to kotlin- in kotlin-metadata-jvm and related projects

Change package, artifact group, artifact name, and Gradle module name to
kotlin-metadata and kotlin-metadata-jvm, respectively.

In Kotlin 2.0, kotlin-metadata-jvm library is promoted to stable, and is
a part of Kotlin distribution now.

Note that kotlinx-metadata-klib is left with org.jetbrains.kotlinx group, artifact name and package
because -klib part is considered not stable and for internal use. Since it is still published via Sonatype,
it should have kotlinx group. Therefore, it will have both classes from kotlin.metadata and kotlinx.metadata packages. This is not a problem, because we already had kotlinx.metadata split package between -jvm and -klib before.

#KT-63219 Fixed

build.gradle.kts

@@ -722,7 +722,7 @@ tasks {
         (coreLibProjects + listOfNotNull(
             ":kotlin-stdlib:samples",
             ":kotlin-test:kotlin-test-js-it".takeIf { !kotlinBuildProperties.isInJpsBuildIdeaSync },
-            ":kotlinx-metadata-jvm",
+            ":kotlin-metadata-jvm",
             ":tools:binary-compatibility-validator",
             ":tools:jdk-api-validator",
         )).forEach {