Personalize code ownership areas (opensearch-project#11600)

Signed-off-by: Peter Nied <petern@amazon.com>

.github/CODEOWNERS

@@ -1 +1,27 @@
-*   @abbashus @adnapibar @anasalkouz @andrross @Bukhtawar @CEHENKLE @dblock @dbwiddis @dreamer-89 @gbbafna @kartg @kotwanikunal @mch2 @msfroh @nknize @owaiskazi19 @peternied @reta @Rishikesh1159 @ryanbogan @sachinpkale @saratvemulapalli @setiah @shwetathareja @sohami @tlfeng @VachaShah
+# CODEOWNERS manages notifications, not PR approvals
+# For PR approvals see /.github/workflows/maintainer-approval.yml 
+
+# Files have a single rule applied, the last match decides the owner
+# If you would like to more specifically apply ownership, include existing owner in new sub fields
+
+# To verify changes of CODEOWNERS file
+# In VSCode
+#   1. Install extension https://marketplace.visualstudio.com/items?itemName=jasonnutter.vscode-codeowners
+#   2. Go to a file
+#   3. Use the command palette to run the CODEOWNERS: Show owners of current file command, which will display all code owners for the current file.
+
+# Default ownership for all repo files
+* @abbashus @adnapibar @anasalkouz @andrross @Bukhtawar @CEHENKLE @dblock @dbwiddis @dreamer-89 @gbbafna @kartg @kotwanikunal @mch2 @msfroh @nknize @owaiskazi19 @reta @Rishikesh1159 @ryanbogan @sachinpkale @saratvemulapalli @setiah @shwetathareja @sohami @tlfeng @VachaShah
+
+/modules/transport-netty4/ @peternied
+
+/plugins/identity-shiro/ @peternied
+
+/server/src/main/java/org/opensearch/extensions/ @peternied
+/server/src/main/java/org/opensearch/identity/ @peternied
+/server/src/main/java/org/opensearch/threadpool/ @peternied
+/server/src/main/java/org/opensearch/transport/ @peternied
+
+/.github/ @peternied
+
+/MAINTAINERS.md @abbashus @adnapibar @anasalkouz @andrross @Bukhtawar @CEHENKLE @dblock @dbwiddis @dreamer-89 @gbbafna @kartg @kotwanikunal @mch2 @msfroh @nknize @owaiskazi19 @peternied @reta @Rishikesh1159 @ryanbogan @sachinpkale @saratvemulapalli @setiah @shwetathareja @sohami @tlfeng @VachaShah