Set up automated deploys

[snorremd]

After building the new version of the image it should automatically be deployed to the server. This can be achieved by exposing the Docker socket to the GitHub action so that it can instruct the docker engine at api.ajanottaja.app to update the api service to the latest digest version.

In order to preserve security the docker engine tcp socket should not be directly exposed to the wider Internet. This remains true even when using credentials on the docker socket. Instead it is probably better to use Tailscale to connect the GitHub action to the api.ajanottaja.app server and then establish a local connection via Wireguard tunnelling.