Provide a way for drivers to add `LIMA_CIDATA_*`

[unsuman]

When external drivers provide boot scripts to Lima, there is no mechanism for those drivers to inject custom LIMA_CIDATA_* environment variables into lima.env. Instead, drivers must perform variable interpolation themselves before returning the boot scripts to Lima.

[AkihiroSuda]

drivers to inject custom LIMA_CIDATA_* environment variables into lima.env

Why inject?

[jandubois]

Why inject?

Maybe "inject" is the wrong word and it should be "define"?

An example is the 02-wsl2-setup.sh script that is currently part of the WSL2 driver.

A slightly more generic version is used by the Kata container driver and the Apple container drivers because it is generic to running a "VM" as a container. So we could have this generalized boot script in the Lima core, and the drivers would just configure it with a few LIMA_CIDATA_* settings instead of having a customized copy of the script.

But maybe this isn't a good idea because it couples the drivers more tightly with the core again, and they should just keep a copy. That is more robust against changes to the core script, that could potentially break a driver.

[afbjorklund]

Injecting boot scripts is not needed for the container drivers, it just needs the WSL2 script to be slightly more generic...

• Remove VMType check from the lima-init boot script #3861