Run github actions in parallel

[eliasbakken]

We are currently running the build sequentially, but the builds should run in parallel to save time.

[eliasbakken]

We might want to start 4 docker containers each with it's own runner instead of having 4 runners directly on the server.
https://baccini-al.medium.com/how-to-containerize-a-github-actions-self-hosted-runner-5994cc08b9fb

[eliasbakken]

4 runners are now working in parallel. Closing.

[eliasbakken]

The server dies, probably runs out of memory or something. Perhaps the resources should be lowered for each container.

[eliasbakken]

The memory is 16 GB, which is a bit low. The swap file is a separate partition of 1 GB and it seems this might be the reason. I've added a second swap file of 10 GB that might work.