CI should enforce no new kconfig options in kernel config on kernel package change/upgrade

@calebccff and I were talking in chat about how to prevent bpo from failing when a kernel's config has new options that require prompting the user to select something. This apparently passes in the gitlab CI, but will fail in bpo as it prompts (and eventually times out).

I think that we can prevent this from happening, and also reduce the amount of kconfig diff over time for some kernel, by enforcing that kernel package maintainers keep the config in pmaports in sync with the kernel version they are packaging. This could be accomplished by doing the following:

1. change pmbootstrap kconfig edit to run make olddefconfig before menuconfig, so new kernel options are added to the config with default values.

2. A new check in pmaports CI that runs make listnewconfig, and fails if anything is returned

Maintainers could also manually run make olddefconfig, but I assume that most folks are primarily managing their kernel's config through pmbootstrap kconfig in a transient chroot, where performing manual steps like that and preserving them in git/pmaports is annoying/inconvenient.