Change Default of disable_predictable_interface_names to "False"

[shurik-io]

Problem

Starting with Debian 10 this setting:
https://github.com/adfinis-sygroup/ansible-role-grub/blob/1a706cac86f77fb5990f70e386bc9d95d3278a0d/defaults/main.yml#L20
is not supported anymore and needs to be removed before upgrading from Debian 9(stretch) to 10 (buster). See here: https://www.debian.org/releases/stable/amd64/release-notes/ch-information.en.html#migrate-interface-names

In EL Distributions, it is the default since major version 7.

Result

As a consequence of this unsupported setting, if this role is applied to Debian 10 installations, the network connectivity can be lost after reboot. (I didn't test it)

Suggestion

So I suggest to change this default to grub_disable_network_predictable_interface_names: False

For backwards compatibility, we should set the old default on Debian <=9 to "True". Because there are still a lot of EL 7 installations running out there with this setting, I guess we can more safely introduce this setting starting with EL = 8.

Please add your feedback, if this change of this settings makes sense and if so, what needs to be done to roll it out safely.