zephyr-kernel: add support for zephyr v3.1.0

This adds support for zephyr v3.1.0. It's not a backport from upstream as meta-zephyr master branch build is still broken as of writing this.

There are several incompatible changes between v3.0 and v3.1 that require us to use separate patches for the ACM console. Other patches needed to be moved around between version too - when we drop v2.7 and v3.0, it will become much cleaner.

On the flip side: lvgl is now upstream so v3.1 doesn't need the lvgl backports. On the flip flip side we need special handling of the DSHIELD option for lvgl as long as we support both v3 versions.

Fixes: #31 (closed)