Add a new make target that provisions dagger-ci declaratively

While at it, add help make target & make it the default.
This explains all make targets. Run `make help` to see it in action 😉

dagger-ci-pr1499-2022-01-26 API token was added as an AGE secret. It can
be accessed only by the intended recipients are able to decrypt it with
their private SSH keys.

    echo "TOKEN" | age -R .age.recipients.txt -o .do.dagger-ci-pr1499-2022-01-26.age

Do not assume that /bin/true exists on hosts running Docker.  Use "true"
and let the system resolve the path.

Re-enable all ssh Universe tests.

Signed-off-by: Gerhard Lazu <gerhard@lazu.co.uk>

pkg/alpha.dagger.io/docker/command.cue

@@ -109,7 +109,7 @@ import (
 				echo "$FINGERPRINT" >> "$HOME"/.ssh/known_hosts
 			else
 				# Add host to known hosts
-				ssh -i /key -o "UserKnownHostsFile "$HOME"/.ssh/known_hosts" -o "StrictHostKeyChecking accept-new" -p "$DOCKER_PORT" "$DOCKER_USERNAME"@"$DOCKER_HOSTNAME" /bin/true > /dev/null 2>&1
+				ssh -i /key -o "UserKnownHostsFile "$HOME"/.ssh/known_hosts" -o "StrictHostKeyChecking accept-new" -p "$DOCKER_PORT" "$DOCKER_USERNAME"@"$DOCKER_HOSTNAME" true > /dev/null 2>&1
 			fi
 		fi