DOC: Cheatsheet change structure
DOC: Cheatsheet change structure

- Add a intro in the page
- Change structure of the page to multiple headline levels.
- Add Kubernetes section
- Add a quick tip how to install tab completion and json support.
- Add some cilium commands.

Signed-off-by: Eloy Coto <2a8acc28452926ceac4d9db555411743254cf5f9@gmail.com>

eloycoto/cilium,michi-covalent/cilium,scanf/cilium,michi-covalent/cilium,eloycoto/cilium,michi-covalent/cilium,scanf/cilium,tklauser/cilium,cilium-team/cilium,tklauser/cilium,tgraf/cilium,cilium-team/cilium,eloycoto/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,eloycoto/cilium,eloycoto/cilium,tgraf/cilium,tgraf/cilium,scanf/cilium,cilium/cilium,cilium/cilium,cilium/cilium,scanf/cilium,scanf/cilium,tgraf/cilium,michi-covalent/cilium,eloycoto/cilium,michi-covalent/cilium,scanf/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,scanf/cilium,eloycoto/cilium