proper disabling 'plymouth'

Created by: philmmanjaro

Seems we have a small issue with disabling 'plymouth' on our current manjaro-tools 0.9.9 release. In XFCE-minimal we have it enabled for only systemd. It is fine for me that OpenRC disables it. So when it is set to false in profile.conf also sysmenu and grub needs to be modified, so we get rid off 'quiet' and 'splash'. grub, if I remember correctly is already fixed for that. Only sysmenu must be edited during creation of the menu.