Revert unified versioning.

Revert "[build][version] generate KonanVersion using data from gradle.properties." 07ae3144de.
Revert "[gradle][test] disable version test" 86ec80a6a7.
Revert "[build][version][doc] update" 94ba9d61a9.

tools/kotlin-native-gradle-plugin/build.gradle

@@ -122,6 +122,8 @@ test {
 processResources {
     // We add konanVersion as a task input to avoid considering this task up-to-date when
     // konanVersion is actually changed and should be updated in the plugin jar.
+    inputs.property("konanVersion", konanVersion)
+    expand('konanVersion': konanVersion)
     from(file("$rootBuildDirectory/utilities/env_blacklist"))
 }