To successfully build an arm image that is usable on eg. the raspberry pi, there is some need for changing options in the build process..
Identified options that need to be changed are:

• architecture
• kernel_flavor
• installed bootloaders

using the current implementation of these scripts we need to create a whole new vyos flavor and duplicating all the options in it.
This could work for now, but things like eg. the kernel version then needs to be changed multiple places when things are upgraded.
the last bullet point is also not possible to change, so thats a new option.

I have made some modifications to this script, that support inheritance of options from other flavor files.
Using this modification makes ut able to extend the platforms without needing to duplicate code between them.
This is not an ideal implementation, but rather a "hotfix" to combat this issue until we have an rewritten configuration builder available.