One way you can do this today is with the defaults key in the gadget.yaml of an Ubuntu Core image.
Regarding passing arguments to installation, I asked about supporting a similar mechanism here: Debugging a snap with failing daemons is difficult
One way you can do this today is with the defaults key in the gadget.yaml of an Ubuntu Core image.
Regarding passing arguments to installation, I asked about supporting a similar mechanism here: Debugging a snap with failing daemons is difficult