[OE-core] RFE: make the init manager an image feature (again)

[Daniel Lazzari]

Sorry I didn't pipe up earlier but we are still working from denzil so I hadn't noticed the steady move away from supporting both sysvinit and systemd in a single distro. We have a similar use case to Otavio where we are hoping to move to systemd this year, but we'll need to use sysvinit for our rescue images since they operate out of a ramfs where space is precious. These images are all built out of the same distro and it seems like it would be a nightmare to try and support 2 distros just so we could have our rescue images.

Daniel Lazzari Jr.
Firmware Engineer
dlazzari at leapfrog.com