move codeowners file to github directory

.github/CODEOWNERS

@@ -0,0 +1,10 @@
+# https://docs.github.com/en/github/creating-cloning-and-archiving-repositories/about-code-owners#codeowners-syntax
+
+csharp-style.md @jbcoe
+htmlcssguide.html @tonyruscoe
+javaguide.html @dimo414 
+lispguide.xml @sfreilich
+pyguide.md @gpshead
+pylintrc @gpshead
+shellguide.md @dimo414 @eatnumber1 @vapier
+/go/ @carrotman42 @gaal @matttproud