Implement strategus battle scheduler

[namidaka]

From crpg created by verdie-g: verdie-g#185

Whenever the preparation and hiring phases of a battle ended, the battle should scheduled on a game server. Since many battles can happen in a day it could be nice to use a technology like kubernetes to easily spawn a game server.

To start this task we should first write a design doc that answers the following question:

• advantages of k8s VS bare metal?
• k8s vs k3s?
• is https://agones.dev useful?
• is https://rancher.com useful?
• how to expose several game servers on the same server (different IP? different port?)?
• when the battle ends, the result should be sent back to the web api service. How does the game server authenticate to the web api. The latter includes a OIDC server, should the game server use that or does kube provide a way to securily make 2 services communicate?
• battles are associated to a region (EU, NA, Asia), the game server should be scheduled on a physical server of that region. How to do that?
• should we also move the crpg web api to kube?
• how does ansible help deploying a kube cluster?
• cRPG use Datadog. How does it integrate with kube?

Since we don't have the files to develop the game server, we can mock it with a simple bash script that sleeps and return 0.