CODEOWNERS: Split codeowners for the documentation
CODEOWNERS: Split codeowners for the documentation

With recent changes to the review process, @cilium/docs was renamed to
@cilium/docs-structure to clarify that reviews from that team should
focus on the documentation's structure rather than its technical content.

Of course, we still need reviews for the technical content. So the next
step, implemented in this commit, is to assign each of the different
reviewer team their own pages in the documentation.

Signed-off-by: Paul Chaignon <a027184a55211cd23e3f3094f1fdc728df5e0500@cilium.io>

michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium