Enable DCM rule double-literal-format.
More details
[here](https://dcm.dev/docs/rules/common/double-literal-format/). This
both forbids trailing zeroes and mandates leading zeroes.
If we would prefer a different style (e.g. prefer no leading zero
instead), just lmk :)
This PR improves the Space Shooter Tutorial as a whole by moving the
setting of component's attributes from their `onLoad` method, to their
constructors.
