Add option for additional kernel parameters

[waynechen55]

• bsc#1231522 makes one point clear that we are looking into feature request to have some point before reboot to collect logs for further analysis and using something that already exists created exactly for this purpose which has the timeout value configurable on the linuxrc command line:

  • https://github.com/yast/yast-yast2/pull/977
  • https://github.com/yast/yast-installation/pull/823
  • https://github.com/openSUSE/installation-images/pull/344 It's even briefly documented at https://en.opensuse.org/SDB:Linuxrc.

• In order to generalize this change and also make things much easier, using "extra kernel params" can help pass any desired parameters to kernel instead of just reboot_timeout.

• Add subroutine get_guest_settings to replicate desired settings to all guests involved.

• Pass extra kernel parameters in guest_installation_run and host_upgrade_generate_run_file.

• By the way, tests/installation/ipxe_install.pm already supports EXTRABOOTPARAMS.

• This pull request should be merged together with https://github.com/SUSE/qa-automation/pull/856 and https://github.com/SUSE/qa-testsuites/pull/1112.

• Verification Runs: