server: split server.cpp code into server/common/task/queue (#17362)

* add server-task, server-common

* add server-queue

* rm redundant includes

* move enum stop_type to server-task

* server : headers cleanup

---------

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

tools/server/CMakeLists.txt

@@ -13,9 +13,14 @@ endif()
 
 set(TARGET_SRCS
     server.cpp
-    utils.hpp
     server-http.cpp
     server-http.h
+    server-task.cpp
+    server-task.h
+    server-queue.cpp
+    server-queue.h
+    server-common.cpp
+    server-common.h
 )
 set(PUBLIC_ASSETS
     index.html.gz