patch 8.2.0516: client-server code is spread out

Problem:    Client-server code is spread out.
Solution:   Move client-server code to a new file. (Yegappan Lakshmanan,
            closes #5885)
diff --git a/src/version.c b/src/version.c
index 078775c..fb73614 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    516,
+/**/
     515,
 /**/
     514,