Add more paths to CODEOWNERS
This splits it up some more; meaning less PRs should hit the top-level
which lists of a lot owners. Still want to keep that list for important
project wide changes
Fixes:
* @bradbeam @chrisohaver @dilyevsky @fastest963 @greenpau @grobie @isolus @johnbelamaric @miekg @pmoroney @rajansandeep @stp-ip @superq @yongtang
+/plugin/pkg/ @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
+/coremain/ @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
+/core/ @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
+/request/ @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
+/plugin/* @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
+go.sum @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
+go.mod @miekg @chrisohaver @johnbelamaric @yongtang @stp-ip
+
/plugin/acl/ @miekg @ihac
/plugin/any/ @miekg
/plugin/auto/ @miekg @stp-ip
