Apply @hide / @SystemApi to android.telecom.*

Move the android.telecom.* namespace back to @hide, and also mark it
with @SystemApi so that system-privileged apps can use them.

Bug: 18302450
Change-Id: I33ae1b9b0dfdb1c5eff51ca3c829196bcfc9411c

telecomm/java/android/telecom/ConnectionRequest.java

@@ -16,6 +16,7 @@
 
 package android.telecom;
 
+import android.annotation.SystemApi;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Parcel;
@@ -24,7 +25,9 @@ import android.os.Parcelable;
 /**
  * Simple data container encapsulating a request to some entity to
  * create a new {@link Connection}.
+ * @hide
  */
+@SystemApi
 public final class ConnectionRequest implements Parcelable {
 
     // TODO: Token to limit recursive invocations