Add link to Noto emoji in README
Add system requirements to README
Reviewed-on: https://git.kske.dev/zdm/envoy/pulls/71
Reviewed-by: delvh <leon@kske.dev>
Reviewed-by: DieGurke <maxi@kske.dev>
Split the README into a project description for users, server admins and programmers. This should be more understandable for users that are not part of the project.