WIP: OLPSUP-10887 Add support for multiple HWIDs

[tkfu]

A software image can be compatible with several different hardware IDs, because different hardware IDs can have the same MACHINE value.

WIP, not yet tested, DNM, etc.

[tkfu]

Note: I realize that I still need to implement a check for invalid characters in GARAGE_TARGET_COMPATIBLE_HWIDS, but if this general approach is ok that should be a pretty quick fix.

[pattivacek]

Looks fine, we should just test thoroughly to make sure it really does what we think it does. I wish we could reuse an existing variables, but it looks like both SOTA_HARDWARE_ID and OSTREE_BRANCHNAME won't work, so this is fine. If we merge this, let's not forget to update https://docs.ota.here.com/ota-client/latest/build-configuration.html#_configuration_variables_in_meta_updater, too.

[pattivacek]

CI failure is unrelated.