Add configure option to not strip binaries

[jo-so]

For distributions, it's needed that the installed binaries are not stripped, because the debug symbols get split of in different packages than the binaries. Debian, for example, does this by replacing the strip program: https://salsa.debian.org/debian/conserver/-/blob/11b6e26ba9d0c2500fbdfe6fb79119804eaf492a/debian/rules#L28 Having a configure flag, e.g. --without-stripping would make this much cleaner.