bmcweb: Remove deprecatd ASIO interfaces

boost::asio::io_service is removed in leiu of io_context, which is a
closer match to the networking TS.  Move us to that implementatio.

This was an automated move using the following command:
git grep -l 'io_service' | xargs sed -i 's/io_service/io_context/g'

Change-Id: I46605521c01f79f86f6901ddf69ddc8c4bc24103
Signed-off-by: Ed Tanous <ed.tanous@intel.com>
diff --git a/include/ast_video_puller.hpp b/include/ast_video_puller.hpp
index 520fc68..c97ca48 100644
--- a/include/ast_video_puller.hpp
+++ b/include/ast_video_puller.hpp
@@ -141,7 +141,7 @@
   public:
     using video_callback = std::function<void(RawVideoBuffer &)>;
 
-    explicit AsyncVideoPuller(boost::asio::io_service &ioService) :
+    explicit AsyncVideoPuller(boost::asio::io_context &ioService) :
         imageInfo(), devVideo(ioService, open("/dev/video", O_RDWR))
     {
         videobuf = std::make_shared<RawVideoBuffer>();