package/urandom-scripts: new package

package/urandom-scripts: new package

The init script S20urandom is used to preserve the kernel's RNG
seed between reboots. This functionality is not required for the
package "initscripts". Further there are use-cases where this script
should not be installed at all (e.g. systems that only have read-only
partitions), but that's currently not possible as the script is
a mandatory part of the package "initscripts".

Let's move the script into its own package "urandom-scripts" and select it,
if the default skeleton is enabled. This maintains backward-compatibility
and allows to deselect it.

Signed-off-by: Christoph Müllner <christoph.muellner@theobroma-systems.com>
[yann.morin.1998@free.fr:
  - extend help text
  - default y if initscripts (instead of skeleton default)
  - allow use with openRC, but not systemd
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>