Revise CODEOWNERS for documentation ownership (#3287)

* Revise CODEOWNERS for documentation ownership

Updated CODEOWNERS to reflect new ownership structure and approval requirements.

* Update CODEOWNERS to adjust ownership rules

Removed Docs Eng ownership from asciidoc files.

* add /extra/

Author: bmorelli25

.github/CODEOWNERS

@@ -1 +1,11 @@
-* @elastic/docs-repo-owners
+# Docs Eng owns the codebase
+* @elastic/docs-engineering
+
+#Readme changes must be approved by writers
+*.asciidoc @elastic/docs-repo-owners
+
+# Writers and Docs Eng share ownership of config files
+/extra/ @elastic/docs-engineering @elastic/docs-repo-owners
+‎/resources/asciidoctor/lib/chunker/v3-mapping.json‎ @elastic/docs-engineering @elastic/docs-repo-owners
+/shared/ @elastic/docs-engineering @elastic/docs-repo-owners
+*.yaml @elastic/docs-engineering @elastic/docs-repo-owners