Move DumpWriter to libnetdutils

resolver related component in libnetd_resolv
needs it to easily print dump log.

Bug: 122564854
Test: built, flashed, booted
      system/netd/tests/runtests.sh pass
      adb shell dumpsys netd, worked fine

Change-Id: Ic97d5f21b738fc3074e9308f4846191e744ed479
diff --git a/server/Process.cpp b/server/Process.cpp
index 1890620..f43e82d 100644
--- a/server/Process.cpp
+++ b/server/Process.cpp
@@ -39,11 +39,12 @@
 namespace android {
 
 using base::StringPrintf;
+using netdutils::DumpWriter;
 using netdutils::Fd;
-using netdutils::UniqueFd;
 using netdutils::isOk;
 using netdutils::makeCleanup;
 using netdutils::makeSlice;
+using netdutils::UniqueFd;
 
 namespace net {
 namespace process {