fix: Server start commands for Docker. (#3160)

With the new atuin-server binary the startup command for the server is
now just start rather than server start. This needs reflected in the
docker compose and k8s configs.

Closes #3159

## Checks
- [x] I am happy for maintainers to push small adjustments to this PR,
to speed up the review cycle
- [x] I have checked that there are no existing pull requests for the
same thing

docker-compose.yml

@@ -2,7 +2,7 @@ services:
   atuin:
     restart: always
     image: ghcr.io/atuinsh/atuin:<LATEST TAGGED RELEASE>
-    command: server start
+    command: start
     volumes:
       - "./config:/config"
     ports:

k8s/atuin.yaml

@@ -15,7 +15,6 @@ spec:
     spec:
       containers:
         - args:
-            - server
             - start
           env:
             - name: ATUIN_DB_URI