syntax and CLI fixes

There's some weirdness in the interaction between Jinja2 directives and
YAML syntax.

Also, `--detach` cannot be used with `--no-start` for docker-compose.

tasks/compose.yml

@@ -33,7 +33,7 @@
             - '{{ beacon_node_metrics_port }}:{{ beacon_node_metrics_port }}/tcp'
             - '{{ beacon_node_listening_port }}:{{ beacon_node_listening_port }}/tcp'
             - '{{ beacon_node_discovery_port }}:{{ beacon_node_discovery_port }}/udp'
-          command:
+          command: |
             {% if beacon_node_network == "testnet2" %}
             - '--run'
             - '--'

tasks/container.yml

@@ -15,7 +15,6 @@
       up \
       --quiet-pull \
       --no-build \
-      --detach \
       {% if compose_recreate %}
       --force-recreate \
       {% endif %}