build kernels with a stable kver

currently each build debian package has the git revision in the package name, that is great for development but for long term maintenance we want to creat specific packages like

linux-image-5.4.0-1-librem5

that is

linux-iamge-<upstream-version>-<abi-version>-librem5

since we otherwise fill up user partitions quickly. These package will then be built with deb-pkg instead of bindeb-pkg so we can (hopefully) upload them to the pureos archive. the amber-phone images can then pull in these instaed of fetching latest, this also gives us a testing period in amber-phone-staging.

this involves several components, just starting here since we need to build such package first (i guess manually would even be o.k. as a start)