Move the job scheduler service code to its own jar file.

- Also remove the dependency from SystemServiceRegistry to JobScheduler

See apex/jobscheduler/README_js-mainline.md for the details.

Bug: 137763703
Test: build and boot
Test: atest CtsJobSchedulerTestCases
Change-Id: I2386c78b7a6085d6e543a63f22cb620c4cabd06a
diff --git a/apex/jobscheduler/service/Android.bp b/apex/jobscheduler/service/Android.bp
new file mode 100644
index 0000000..ca6dc45
--- /dev/null
+++ b/apex/jobscheduler/service/Android.bp
@@ -0,0 +1,15 @@
+// Job Scheduler Service jar, which will eventually be put in the jobscheduler mainline apex.
+// jobscheduler-service needs to be added to PRODUCT_SYSTEM_SERVER_JARS.
+java_library {
+    name: "jobscheduler-service",
+    installable: true,
+
+    srcs: [
+        "java/**/*.java",
+    ],
+
+    libs: [
+        "framework",
+        "services.core",
+    ],
+}