Openmage on K8s.

[m-michalis]

My experience on kubernetes is only about 2 months. I've only played locally with minikube. I've wrote this just to get started on this conversation (suggested by @Danieleeffe1) because I did not find any actually useful articles on the web.

This PR just explains how I approached this.

My concerns:

• database files on, lets say, high availability cloud storage have latency?
• Media and skin folders? Probably mount ex. s3 bucket via persistentVolume. (with the right setup you can just connect cloudfront to that s3)
• php-fpm (user: www-data) and nginx (user: nginx) images should run with the same uid and gid while having /media/ and /skin/ shared?
• any optimizations for db reads and writes regarding having a "true" db for admin and cron and replicas for frontend?
  • I've only worked with small scale (10 orders/minute) projects, so maybe on 1000/sec db should be split/cached (a whole new chapter here)
• how openmage db upgrade policy should work? (first do the admin pod, then the replicas?)
• other cache layers?
• security?

PS: Also this is my very first PR (even as a draft)(in any repository ever) while being a magento developer for over 5 years. 😅

edit: typo