[K/N][publish] Publish kotlin-native-compiler-embeddable.jar

Add an ability to publish kotlin-native-compiler-embeddable.jar and
sources to maven. Adds necessary for that sourcesJar and javadocJar
tasks. Note that Native distribution uses this jar without a version postfix.
Also cleaned up the obsolete backend.native publication and renamed 
project to match its name.


Merge-request: KT-MR-12974
Merged-by: Pavel Punegov <Pavel.Punegov@jetbrains.com>

kotlin-native/prepare/kotlin-native-compiler-embeddable/testData/projects/smoke/Smoke.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package smoke
+
+fun main(args: Array<String>) {
+    println(args)
+}