Add support for one system with two inits

[konimex]

This PR adds support so artools-iso can generate an ISO which should work with two init systems.

However, eventually this PR will also report the progress of supporting two different init systems in Artix.

Prerequisites:

• [ ] No package owns sysvinit-compatible binaries like /usr/bin/init
  • Use halt for wrappers around poweroff/shutdown/reboot
  • Use an alpm hook so when we detect two init systems installed we can make users choose which init to use on next reboot (However, this shouldn't trigger when we generate the ISOs so the users can choose them in initramfs via artix_init instead)
• [ ] Ensure that OpenRC and runit-artix (the init part of runit) doesn't conflict.

Live system:

• [x] Add init module for initramfs
• [ ] Add dual init option for artools
• [ ] Calamares support
  • Either we utilize the use of netgroups or we add a new module. This time when we add both package the alpm hook should be triggered.
• TBA

[udeved]

Excuse my ignorance, but what is the point of two inits on a live system? I don't really get it, ie I am not really in favor of this.

Why do we need two init systems in parallel installed on a live iso? Calamares cannot handle dynamic netgroups and netgroups don't have alternatives implemented. Two inits to select could royally screw up the install. I am in favor of keeping init separate on iso.

[konimex]

Hmm.. Alright, then. I'll close this one.

[udeved]

Just saying, keep the partially noobish users in mind. They have no clue about init or package selection. ;)