Cluster IDs should not have leading dash

Since we use URL-safe base64 encoded Uuid's for cluster ID, it is possible for dash ("-") characters to be present in the ID string. When a cluster ID has a leading dash, we can run into problems when running the Kafka bash scripts.

For example, if the ID "-Xflm1nKSfOK8QGt_AXhxw" is generated with "random-uuid" sub-command of kafka-storage.sh, we would then normally format the log directories like:

./bin/kafka-storage.sh format --config ./config/kraft/controller.properties \
    --cluster-id -Xflm1nKSfOK8QGt_AXhxw

This will not parse correctly as the argument parsing library will treat the cluster ID as an argument. It leads to the following error:

usage: kafka-storage format [-h] --config CONFIG --cluster-id CLUSTER_ID [--ignore-formatted]
kafka-storage: error: argument --cluster-id/-t: expected one argument

This can be worked around by putting the ID in quotes, or by using an "=" between the "--cluster-id" and the Uuid.

We can solve this going forward by not generating random Uuid's that contain a leading dash.